WOMEN who become pregnant while living with a partner are more likely to give birth to a boy than are women who conceive while living alone, a study of nearly 90,000 births in the US suggests. Could this be why the birth rate of boys is dropping in some developed countries?
On average, about 51 per cent of births are boys, but some studies show this figure falls when food is scarce. The evolutionary rationale is that it takes more resources to raise boys, who tend to be larger than girls. But the effect of a committed partner on…
