Pink jobs, blue jobs

Does your job determine your baby’s gender? I find it hard to believe.

Couples desperate to produce a son could boost their chances if one or both of them switches to a “masculine” profession such as engineering or accountancy, a report said.

Equally, those keen for daughters are more likely to have success if they hold down “caring” jobs such as teaching or nursing, a British study has discovered.

According to a London School of Economics survey printed in the Journal of Theoretical Biology, engineers and other “systemisers” give birth to 140 boys per 100 girls, while nurses have 135 girls for every 100 boys.

(Satoshi) Kanazawa predicted that a physicist and a mathematician would be the most likely pairing to produce a boy, while a therapist and a chat show host would be odds-on favourites for a daughter.

One evolutionary biologist guesses that a fetus would encounter more testosterone in the womb of an engineer mother. So why would the father’s occupation matter?

Update: OK, here’s a link to the article. It doesn’t say that changing jobs will change the sex of your future children. The theory is that people with “systemiser” brains are more likely to have male children, while people with “empathizer” brains are more likely to have girls.

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Comments

  1. Because female engineers are most likely to marry those they met on the job – other engineers. Women are a rarity, and are surrounded by men.

  2. Mr. Davis says:

    Why would the father’s job matter? The child’s sex is determined by the father’s genes. A hypothesis is that men who produce a high proportion of sperm carrying the male gene will be more likely to work in “masculine” professions.

  3. I think I saw a report somewhere to the effect that fighter pilots tend to have more daughters.

    Yes, “fighter pilot” is a “caring” profession, but not exactly in the way the study authors probably had in mind…

  4. Jeff Boulier says:

    It’s always dangerous, but I’m going to assume the study was well designed and focus on possible explanations.

    The initial genetic decision as to the child’s sex is the male’s. If a byproduct of the constellation of genes that tends to produce good engineers results in a larger number of “fit” sperm bearing the Y chromosome relative to sperm with the X, then engineers will tend to have more sons.

    The second “decision” is primarily the female’s — once the embroyo is formed, does implantation succeed? Is the mother able to carry her child to term? There are various factors that cause a difference in survivability between male and female embryos. These factors are actually in play for both the child and its mother, so another set of explanations for the difference are that “male engineer” embryos are more likely to survive, or perhaps female engineers provide friendlier womb environments for their male children.

    Yet another possibility is that there are cultural factors in play. If a large number of engineers come from cultures which have a strong son preference (e.g. Korea, China), then this will be reflected in the sex of their children. Even without selective abortion, if the rule is that parents keep having children until a male child is born, then the ratio works out to something like two-thirds male (that’s a guess, I didn’t bother to work out the math).

  5. Here’s the original paper, which says nothing like what the press reports say. No, your job does not determine the sex of your baby, but the correlation between those with systemizing brains and systemizing jobs is pretty clear.

  6. Steve LaBonne says:

    “Here’s the original paper, which says nothing like what the press reports say.” Gee, what a surprise. 😉

  7. One evolutionary biologist guesses that a fetus would encounter more testosterone in the womb of an engineer mother.

    What would that have to do with the sex of the child? An evolutionary biologist must not be the same as a real biologist.

  8. Oh, it looks like it’s the prenatal exposure of the parents to testosterone which is supposed to influence the sex of their children.

  9. Richard Brandshaft says:

    “Couples desperate to produce a son could boost their chances if one or both of them switches to a “masculine” profession such as engineering or accountancy, a report said.”

    Big surprise: innumeracy in the press. Even before I saw the original article, I knew that first sentence had to be wrong. If the correlation wasn’t some kind of numerical illusion, it had to be a common cause (something the helps people to choose jobs also helps determine the sex of their children) rather than the job causing a gender imbalance.

    It reminds me of a story I heard in the 1960s. Someone discovered that a predictor of children’s academic success was whether they lived in a home with a dictionary. (A realization of how sheltered I was. It had never occurred to me before that some families didn’t have dictionaries.) Naturally, some idiot congressman suggested we buy all poor families dictionaries.