Before we tackle this question, let’s review some fundamental concepts of evolutionary biology and psychology. You need to have an understanding of these concepts before proceeding and if you’re already familiar with them a nice little review won’t hurt.
Reproductive potential
Reproductive potential
It’s the number of children an individual organism can produce. In humans, males have a higher reproductive potential than females because they produce much more sperm in their lifetime than females produce eggs.
Reproductive certainty
While males have a higher reproductive potential, females have a higher reproductive certainty. This means that almost all females reproduce whereas a lot of men do not get a chance to reproduce at all.
Reproductive success
Our psychological mechanisms are wired to seek reproductive success i.e. successfully passing on as many genes to the next generation as possible (having kids who can successfully reproduce).
Keeping these concepts in mind, let’s delve into the eternal question of whether human parents prefer sons or daughters…
More sons = greater reproductive potential
Since human males have a very high reproductive potential compared to females, having more sons means more of your genes have the chance of making it to the next generation.
When it comes to reproductive success, more is better. Having a head start is always preferred. If conditions turn out bad later and some genes die, others can survive.
Therefore, in general, parents tend to prefer sons over daughters under average circumstances.
What exactly do I mean by ‘average circumstances’?
Average circumstances mean that the factors that influence reproductive success are not extreme.
Now, there are a lot of variables that can influence reproductive success but the most important of them all is ‘availability of resources’.
Now, there are a lot of variables that can influence reproductive success but the most important of them all is ‘availability of resources’.
Hence, in this case, ‘average circumstances’ would mean that the resources that parents can invest in their children are neither large nor small, they’re average.
What if the resources are not average? What if the parents have less or more available resources? Will that affect their preference for sons versus daughters?
The answer is yes.
When available resources are meager
Reproductive success is both a function of reproductive potential and reproductive certainty. It’s just that under average circumstances, reproductive potential becomes more important because there’s already a good degree of reproductive certainty.
But when the available resources are meager, the balance of the equation shifts. Now, reproductive certainty becomes more important. In other words, when available resources are less, reproductive certainty becomes a more important determinant of reproductive success.
As you might have guessed, in such a situation daughters become more preferable than sons.
When you don’t have a lot of resources to invest, you can’t run the risk of producing sons whose reproductive certainty is low compared to daughters. They may not get a chance to reproduce at all, especially when their parents can invest very little in them.
There is a direct relationship between the reproductive success of males and their resourcefulness.
Therefore, when there’s a resource constraint, parents can’t simply go for the possibility of passing on a greater number of genes to the next generation. They’ve got to aim just for certainty. Beggars can’t be choosers.
It isn’t surprising, therefore, that women without a long-term partner or married to low-status men tend to produce an excess of daughters while women married into resourceful families tend to produce an excess of sons.
The logical conclusion that we can make from all that we’ve discussed above is that parents who have slightly more than average resources should show no preference towards either boys or girls. They should prefer boys and girls equally.
However, should economic conditions worsen, they’re likely to prefer girls over boys.
An interesting study conducted by researchers from two business schools showed that parents who had both daughters and sons spent more on daughters in bad economic times.
These parents seemed to unconsciously understand that in tough economic conditions reproductive certainty became more important than higher reproductive potential.
Even more intriguing is the fact that such preferences also exist at the womb level. When resources are scarce, female biology suppresses boys’ survival in the womb. The result being that mothers give birth to fewer males than normal.
These parents seemed to unconsciously understand that in tough economic conditions reproductive certainty became more important than higher reproductive potential.
Even more intriguing is the fact that such preferences also exist at the womb level. When resources are scarce, female biology suppresses boys’ survival in the womb. The result being that mothers give birth to fewer males than normal.
Here’s a short video discussing this…
References:
Cameron, E. Z., & Dalerum, F. (2009). A Trivers-Willard effect in contemporary humans: male-biased sex ratios among billionaires. PLoS One, 4(1), e4195.
Durante, K. M., Griskevicius, V., Redden, J. P., & White, A. E. (2015). Spending on daughters versus sons in economic recessions. Journal of Consumer Research, ucv023.
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