Humans have known that it takes a man and a woman to make a baby for tens of thousands of years, but the details of how women get pregnant, why they might not get pregnant and what influences a baby’s gender were subject to some strange misconceptions.
Perhaps the strangest was the idea posed by Greek philosopher Plato (428 BC to 348 BC). He thought that a woman’s womb was a living animal that needed to become pregnant or it might wander around a woman’s body, a theory that surprisingly remained popular until well into the Middle Ages. This wandering was said to make women “hysterical,” a state of mind named for the Greek word for uterus.
The Greek physician Hippocrates (460 BC to 370 BC) believed that both men and women contributed a “seed” to make a baby, but blamed all cases of infertility on the woman. Aromatherapy was then considered a viable treatment for infertility but proved generally ineffective.
The 11th-century female physician Trotula of Salerno was the first to suggest that infertility might have something to do with men, but her theory did not gain wide acceptance and women continued to be solely blamed for their inability to conceive as late as the 20th century.
Throughout history women have been stigmatized, shamed, divorced and even executed for not having male offspring. Henry VIII of England executed and divorced several wives for their inability to provide him with a male heir.
Today we know that women carry the XX chromosome and men carry the XY chromosome which determines a child’s gender, but for centuries, a lack of sons was also considered a woman’s fault. Women did what they could to have a male child when that was important in their culture, but it rarely worked. Such efforts included eating certain foods, having sex in certain positions and at strategic times.
An ancient Chinese Lunar Conception calendar was based on the idea that the month you conceived in could predetermine the sex of your child, so a woman looked up her age, then found the month that would improve her odds of having the desired gender.
While the right timing in a woman’s cycle can improve the odds of conception, there’s no proof that timing influences the child’s gender. A study concluded that the odds of determining gender based on the lunar calendar were no better than tossing a coin.
In Elizabethan times it was mistakenly believed that a woman could only become pregnant if she enjoyed the sex and had an orgasm, which enabled her to “spend her seed.” This theory, originally promoted by Hippocrates, did not bode well for the prosecution of rape cases that resulted in pregnancy.
At a loss to explain multiple births many cultures came up with theories as to why it happened and what it meant. Twins were considered a good omen in a few cultures, while in others they were an evil omen requiring a mother’s expulsion from her community. Women carrying multiples were often eyed suspiciously. Grimm’s Fairy Tales, written in the 19th century, featured a story in which a women with a multiple pregnancy is accused of having relations with more than one man, because otherwise she could not be carrying more than one baby.
Today we have a better understanding of multiple births and know that’s not true. Fraternal multiples are siblings, conceived when more than one egg is fertilized at the same time. In the case of identical twins, one egg is fertilized and then divides into two or more embryos.
The Nigerian village of Igbo Ora has one of the highest rates of twin births in the world, and some say it’s due to the large quantity of yams eaten there. There may be some truth to that since yams contain phyto-estrogens that are linked to fertility but no conclusive studies have been done.
Twins were once thought to run in families, but a recent study showed that it’s not true with identical twins. There is a gene that makes a woman more likely to release two or more eggs during ovulation and thus more likely to have fraternal twins or multiple births. That gene does run in families.