As a follow-up to my post about parasites, a recent study shows that women with latent Toxiplasma infections are much more likely to have baby boys that girls. The normal sex ratio is 0.51 in favor of boys (104 boys are born for every 100 girls), but in toxiplasma-infected women the ratio is as high as 0.72 (260 boys for every 100 girls).
A new or alien disease doesn't have to kill the infected population to wreak havoc on the population. Imagine* the social changes that would take place if most of the babies were boys.
*Actually there is no need to imagine - this scenario is playing out in some parts of China today, by choice, rather than infection.
Tags:toxiplasma, sex ratio