Tag: reproduction

Posted in Science & Nature

Virgin Birth

Posted on by Jinavie

Although the concept of virgin birth (i.e. conception without intercourse) is common in many religions, there is no conclusive evidence of actual human virgin birth in recorded history. Except in one medical article written in 1874 by a Dr Capers.

In this article, Dr Capers describes a case study of a miraculous conception during the Battle of Raymond during the US Civil War. A soldier was shot in the testicles and the musket ball carried the non-musket ball (read: testicle) into the uterus of a girl working in a nearby field. The doctor attended to the girl who was shot and treated the wound in her abdomen. The bullet was not found.

Over the following nine months, the doctor realised the girl was pregnant, although she claimed to be a virgin. After nine months, a healthy boy was born. Stranger yet, the doctor realised the boy’s scrotum was unusually swollen and upon examination, found that he was carrying the musket ball that impregnated the girl in the first place. He thus concluded that the testicle that was carried by the musket ball was lodged inside her uterus and sperm leaked out. The soldier was eventually found and was told about this bizarre story and the two were married.

This case study has become a famous story told by doctors around the world. Unfortunately, it is completely false and the doctor who wrote the article admitted to faking it to amuse himself. Ergo, there are still no recorded cases of a virgin birth in humans.

The closest to a virgin birth that was recorded is a case study of a young woman who was performing oral sex on a man. She was found by her boyfriend during the act and the boyfriend stabbed her and her lover with a knife. The knife injured her oesophagus, causing the sperm in it to track down the abdomen and down to her reproductive organs. By a stroke of luck, an egg was misplaced during ovulation, causing it to drift into the abdomen instead of the fallopian tube (ectopic pregnancy), and met with the sperm. The egg was then fertilised and the girl presented to the hospital three months later with excruciating abdominal pain. The ectopic fetus was removed.

Posted in Science & Nature

Caesarean Section

Posted on by Jinavie

(To read about how babies are made and born, read the From Cell to Birth miniseries! https://jineralknowledge.com/tag/arkrepro/?order=asc)

Most animals give birth through a female’s vagina. Of course humans are the same when it comes to natural birth, but nowadays, it is not uncommon to find women wanting a caesarean instead of the traditional method. A caesarean (also called C-section) is a surgical procedure where the fetus is taken out by cutting through the lower abdomen into the uterus. The history of caesareans is quite dark. Back in the old days when medicine was not advanced, caesareans were mostly used to rescue fetuses from mothers who had died during childbirth. The first record of a successful caesarean where the mother survived dates back to the 1500s. Many people believe the word “caesarean” came from the Roman emperor Julius Caesar, who was allegedly born via a caesarean. However, it was rare for caesareans to be performed in Roman times and even if they were, the mothers almost certainly died in the process. Given that his mother was alive and healthy well into his adulthood, it is highly unlikely that Caesar was born by caesarean (there are no concrete records of it either).

There is much debate to whether a caesarean is better or worse than natural birth (except in emergency situations where a caesarean is required). According to research (in cases without known risks to the fetus), the mortality rate is definitely higher in babies born by caesarean compared to those born naturally. This is most likely due to a caesarean bypassing some of the physiological changes that occur during vaginal birth.

Another debate is about the use of general versus regional anaesthesia (spinal block) when doing a caesarean. A fascinating fact about childbirth is that when a baby is born, it cries to expand its lungs but then quietens down for about an hour (unless it is in pain or there is some stimuli). This is possibly a mechanism to allow bonding between the mother and baby. New mothers often remember the moments following the birth of the child as extremely emotional and blissful. Contrastingly, mothers who are under general anaesthesia and not awake when their child is born bond less with the baby initially (some mothers do not even recognise the baby as their own). Thus, unless it is an emergency caesarean, a spinal block (which allows the mother to be awake and painless) is preferable over general anaesthesia.

Lastly, it is common tradition to cut the umbilical cord straight after the child is born. But is this okay? When the fetus is in the uterus, it shares its cardiovascular system with the placenta. The umbilical cord connects the two and carries blood to and fro. At any given point, the placenta contains 30~50% of the fetal blood. If the umbilical cord is suddenly cut, the fetus essentially loses this blood, being born in a state of low blood volume. If you look at the umbilical cord, you can see that it is about 1m in length, which is enough for the baby to be put next to the mother’s breasts for breastfeeding and bonding. Perhaps we are cutting the cord too soon, not letting the blood flow back from the placenta to the fetus.

If you think about it, humanity has been giving birth without too many problems to survive generation after generation for 200,000 years (otherwise we would not exist). Although the mortality rate was high, Mother Nature has optimised childbirth over time through evolution. Ergo, it is possible that modern medicine is intervening too much in a natural process. We must always consider whether medical advances are helpful or harmful to us.

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Posted in Science & Nature

Red Queen’s Hypothesis

Posted on by Jinavie

In Lewis Carroll’s Through the Looking-Glass, there is a scene where the Red Queen says to Alice: “It takes all the running you can do, to keep in the same place”. Essentially, it means to spend all the effort you can just to keep the status quo. In life, there are so many times when it seems like you’re frantically running just to realise that no progress has been made. Interestingly, the same rule is seen in biology and evolution.

The simple rule of natural selection is that the best adapted species wins. Unfortunately, this means that no matter how well you are doing in the environment, as soon as another species becomes better adapted to a new change, you become the lesser species and eventually destroyed. To prevent this, a species must continuously evolve and adapt just to stay in the same position. Nature despises stagnancy and loves progress. For example, a predator always strives to evolve to better catch the prey while the prey evolves to avoid the predator. This cat-and-mouse arms race allows for continuous evolution and ever-improving fitness. This is the Red Queen’s Hypothesis.

A fascinating extension of the hypothesis is that it may be a cause for having sex. Sex is one of the most intuitive inventions of Mother Nature that allows for massive genetic variation. The Red Queen Hypothesis has been used to suggest that this may have evolved to speed up the process of evolution so that hosts could beat parasites in the ongoing arms race. The greatest act of love may simply be a mechanism for us to stay competent in this ever-changing world.

Posted in Psychology & Medicine

Pink

Posted on by Jinavie

Normally, babies are dressed in blue for boys and pink for girls to differentiate their sex. Even in adult societies, the colour pink is associated with women. As some women have a particular fondness for the colour, the stereotype deepens. Why is femininity related to the colour pink?

The easiest explanation is that it is simply a social construct. In other words, as society says “pink is a girl’s colour”, the stereotype is set. Although this may seem like a simple answer, it shows the power of the majority’s opinion and stereotypes. As evidence to this theory, one can consider the following excerpt. It is taken from an American magazine from 1918:

“The generally accepted rule is pink for the boys, and blue for the girls. The reason is that pink, being a more decided and stronger colour, is more suitable for the boy, while blue, which is more delicate and dainty, is prettier for the girl”.

As you can see, in the past the opposite was the social norm where pink was a boy’s colour. This shows that pink and women have no direct links. This norm was flipped around the 1940’s and pink is still the symbol for femininity.

There is also some scientific data attempting to explain the phenomenon. One study proposed that as prehistoric humans had gender roles where the men hunted and the women gathered, women evolved to seek out red berries, which are ripe and delicious. Thus, they still have a soft spot for pink things. Also, as one can see from cheek blush and red lipstick being common make-ups, women like to accentuate a flush on the face. Pink cheeks and red lips signify that they are healthy and ready for reproduction, causing men to find the colour attractive. Pink clothes further enhance this effect to make the woman look more attractive. A similar technique is used by monkeys (especially baboons) where the female’s backside turns pink or red to alert the males that she is ready to mate.

Posted in Science & Nature

Grandmother Hypothesis

Posted on by Jinavie

There are many physiological events that puzzle scientists. Menopause is one of these as it is very uncommon in other mammals. Why do human females stop having periods after aging? From an evolutionary point of view, an organism that has lost reproductive function cannot aid evolution and thus it is a mystery how a trait like menopause survived natural selection. The leading theory in how such a phenomenon happened is the grandmother hypothesis.

According to this hypothesis, as humans are social animals menopause can still be an evolutionary advantage despite not being able to produce offspring. This is because older women can invest the massive amount of energy and time required to upkeep childbearing in other places. For example, they can help their family and society grow by working or taking care of children instead. Furthermore, as the probability of miscarriages and congenital defects rise with aging (generally after a woman hits the age of 30, the chances of a healthy pregnancy decreases), menopause has the function of protecting the gene pool of the species. These facts combined lead to the conclusion that after an individual has reached a certain age, taking care of their children or grandchildren instead of birthing more offspring is more effective in propagating their own genes. Also, there is no one that can propagate massive amounts of wisdom and information to the next generation like the elderly.

In modern society, menopause has more significance than at any point in the history of human beings. As our average life span has surpassed 80 and heading towards 90, almost half of a woman’s life is post-menopause. In some ways, the grandmother hypothesis contains within it a certain philosophy regarding life. As we age, we give birth to children and raise them until they become independent, at which point we escape our basic biological duty of reproducing to lead our “own” lives. Senescence is like a second spring after one’s “biological” life. It is the start to a new life – a more “human” life of your own where you can focus on seeking pure happiness.

Posted in Science & Nature

Lemming

Posted on by Jinavie

When you think of lemmings, you are bound to think of two things: a small, round rodent and mass suicide. The reason being, we have been taught as children that lemmings often commit mass suicide. This theory originates from the late 19th century when scientists could not figure out why lemming populations seemed to spike rapidly and then fall just as fast. In 1908, a man named Arthur Mee proposed that they kill themselves, writing so in the Children’s Encyclopaedia. He posited that as an overpopulation of lemmings could devastate the European ecosystem, the lemmings were naturally controlling their own population count. His theory was backed by a documentary made in 1958 called White Wilderness that showed a footage of a herd of lemmings leaping off a cliff to their death.

However, this “fact” has a severe flaw. Lemmings do not commit mass suicide. If you think about it for even a second, the thought of an animal that commits mass suicide (other than human beings) is preposterous as the species would die out. The reason why the lemming population spikes is the same as for mice and rabbits: they pride themselves in extreme reproductive abilities. A female lemming can have up to 80 babies in one year. If the population grows at such an alarming rate, then as explained above, the environment would not be able to support it. This causes the lemming population to plateau, not rising or falling, as there is not enough food to feed all the lemmings. However, due to the shortage of food, the lemmings become desperate and hungry. To find more food, the lemmings begin a migration, but the combination of hunger and being in heat causes them to act irrationally and wild. The result is a massive herd of hungry, stupid lemmings frantically running around all over the place. This leads to some lemmings accidentally slipping off cliffs and drowning in the river while swimming. This is not suicide.

Then what was the strange phenomenon of mass suicide depicted in White Wilderness? The answer is simple: it was staged. The producers tried to replicate Mee’s theory by importing a dozen lemmings and filming them running around the place. Then why did these lemmings commit suicide? Because the producers launched them off a cliff from a turntable.

Posted in Science & Nature

Praying Mantis

Posted on by Jinavie

The praying mantis is sometimes considered a symbol of ultimate female empowerment. After mating, it has been observed that the female would immediately proceed to kill the male she just mated with and eat his corpse, head first.
However, one thing that is less known is that this act – known as sexual cannibalism – occurs almost exclusively in captivity. This is because in the wild, a male runs off quickly after mating to avoid a grim fate. The female, with a massive appetite after the tiring act of copulation, looks for a source of nutrients to upkeep her pregnancy. As in a captive environment the male cannot run far and the female cannot hunt easily, she opts to eat the male as this is more beneficial for her. Furthermore, as mantises have very sharp vision, it is highly likely that the observing scientists (giant, towering figures dressed in white) will intimidate the female mantis. The anxiety caused by the observation would thus make the female act more violently.

The theory that lab intervention caused sexual cannibalism was proven when mantises stopped cannibalising after being fed ad libitum (until they were full). In fact, the female would carefully observe the courtship dance of the male and decide whether he is worthy of mating. This courtship dance also has the effect of switching the female’s priorities from feeding to mating.

It has also been suggested that females may choose to eat the males they do not deem worthy (before mating), or that the males are sacrificing themselves to improve the chance of fertilisation. This is supported by evidence of decapitated male mantises copulating more vigorously and mounting the female for much longer periods. 

In other words, male submissiveness can be a factor in reproductive success.

Posted in Science & Nature

From Cell To Birth: Childbirth

Posted on by Jinavie

The onset of labour signals that the birth of the child is imminent. Strong contractions of the uterus under the influence of oxytocin cause intense pain for the mother. This escalates as oxytocin creates a vicious cycle for more and more powerful contractions. Other signs include a bloody show, where blood and mucus leaks out, and the water breaking, where amniotic fluid bursts out as the membranes rupture.
When the cervix has fully dilated to 10cm wide, the baby is ready to come out, and this is the end of the first stage. It may take over 24 hours for this stage to be over – all the while the mother is in extreme pain as her body transforms for the process.

The second stage concerns the delivery of the baby, and follows a precise series of steps.

  1. The baby, oriented head-down, facing either right or left, leans against the pelvis.
  2. The baby begins to descend, passing through the pelvis.
  3. It flexes its head as it comes through the cervix, turning towards the mother’s back as it does so.
  4. As the head crowns, the baby turns back to its side-facing position so the shoulders can come out.
  5. The rest of the body comes out with the shoulder. Forceps may be used to help.

The passage of such a large head and body is only possible through the massive dilation of the cervix, the stretch of the vagina, and the soft, malleable skull of the baby (a newborn’s head often looks conical and alien-shaped). Quite often, the opening of the vagina is not wide enough, and the opening may be cut open more to ensure it does not rip.

After the baby is safely delivered, the umbilical cord and the placenta are also delivered, thus ending the third stage (afterbirth). The cord is clamped and cut, and the baby is then thoroughly checked to ensure it is healthy and has no developmental issues.

Although in the past childbirth was extremely risky and often led to the death of the mother and/or baby in the process, nowadays protocols and health professionals ensure that both survive the procedure, thus ending the incredible 40-week journey until the birth of a new life. Only after understanding the arduous steps and the risks a mother takes to give birth to her child can one truly appreciate the value of life.

(Full series here: https://jineralknowledge.com/tag/arkrepro/?order=asc)

Posted in Science & Nature

From Cell To Birth: Growth

Posted on by Jinavie

After implantation, the embryo quickly grows from a ball of cells into what will be a fully-formed baby. However, it first needs a way to feed: the placenta.
It is an organ that actively takes nutrients and oxygen from the mother’s blood, exchanging it for the embryo’s waste products. It is extremely effective in keeping the fetus alive and protects it from infections or the mother’s immune system.
The blood is carried by the umbilical cord, which plugs into the belly button. This cord is the lifeline throughout term, and disrupting the blood supply will lead to permanent brain damage or even death.

In the first 10 weeks, the blastocyst develops into a very primitive disk-like object that shares no resemblance to a person. It keeps growing and differentiating at a rapid rate (almost doubling in size per week) until it forms an embryo that is more familiar, roughly about week 6. Interestingly, a human embryo looks almost identical to embryos of rabbits, chickens, turtles and fish, showing how all animals shared a common ancestor in the course of evolution. At this stage, the embryo has features such as gills, a tail and a fish-like appearance.

After 10 weeks, the embryo has grown to about 5~8cm (almost 10~20 times the size at week 6), and is now called a fetus. It begins to properly grow organs, and resembles a miniature baby with primitive features.
It continues to grow for the next 30 weeks, continuously relying on the mother for nutrition and life support.

Many different factors contribute to premature birth and IUGR (intrauterine growth restriction), which leads to the birth of a small baby. This may result in less developed organs (especially the lungs) and may affect the health of the newborn throughout its life. There are also many poisons known to harm the development of the embryo/fetus, such as alcohol, nicotine, cocaine, heroin and much more. These should be avoided from a few weeks before conception onwards (even after birth while breastfeeding).

By about 38 weeks, the lungs (the last organs to fully mature) are ready and the fetus is upside down. It is ready to leave the womb, and thus sends a signal to the mother, known as labour. This is when the arduous process of childbirth begins.

(Full series here: https://jineralknowledge.com/tag/arkrepro/?order=asc)

Posted in Science & Nature

From Cell To Birth: Implantation

Posted on by Jinavie

When an egg is fertilised by the sperm, it is called a zygote. This zygote immediately starts to divide at an exponential rate, to achieve the feat of transforming from a single cell to a 3kg baby. The division and growth happens as the zygote slowly drifts towards the uterus, where it can secure itself.

30 hours after fertilisation, the zygote is now 2 cells.
72 hours, the zygote is now 16 cells.
96 hours, the zygote is now a ball of over 60 cells, and now called a morula.
108 hours, the morula has a cavity inside, and is called a blastocyst.
The blastocyst, essentially a shell of cells with a mass of cells at one point, hatches out of the zona pellucida as it is now much bigger.
To gain the massive amount of energy required for development, the zygote eats up simple sugars in the fallopian tube during its travel.

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As mentioned before, when pregnancy does not happen, the endometrium is shed and flushed out. To prevent this, the blastocyst secretes something called βhCG, keeping the corpus luteum alive, which secretes progesterone to maintain the endometrium. As the endometrium is the fertile “soil” where the embryo will grow, this is a vital step (βhCG is the hormone tested in a pregnancy test).
When the blastocyst reaches the uterus, it finds a safe spot on the endometrium, with the inner cell mass facing the wall. This is where implantation begins.

After clinging tightly to the endometrial cells, the blastocyst fuses some of its cells into a digging tool that can eat away at the endometrium. As it digests away the cells, the blastocyst slowly burrows in until it is completely embedded inside. Cells invade the hollowed space, firmly securing the blastocyst while destroying blood vessels and glands to release nutrients, securing a supply line. Now, it can start its rapid development into an embryo as it leeches away the mother’s nutrients.

A foreign body latching on to the host’s cells, digesting away tissue and leeching blood and nutrients – an embryo acts exactly like a parasite, to ensure that it can safely survive the 40-week gestation. In fact, an embryo can implant itself almost anywhere in the body, such as the fallopian tubes, ovaries or even the gut, as long as there is a secure blood supply. This is called an ectopic pregnancy, and can be an extremely dangerous scenario to both the mother and developing fetus.

(Full series here: https://jineralknowledge.com/tag/arkrepro/?order=asc)