A new study found would-be mothers who feel overwhelmed or depressed are at greater risk of suffering a miscarriage if they are pregnant with a boy.
Scientists at Columbia University in New York said that, in many cases, women will not yet have realised they have conceived when the pregnancy fails due to stress.
The team correlated birth outcomes in a group of 187 pregnant women with 27 indicators of psychosocial, physical and lifestyle stress.
They noted that the boy-to-girl ratio in women who were physically stressed was 4:9, and 2:3 in women who were psychologically stressed.
This is compared to 105:100 boy-girl ration across the whole population.
Published in the journal of the Proceedings of the National Academy of Sciences, the study appears to explain longstanding trends showing an increase in births of girls relative to boys following national traumas, such as 9/11, the assination of JFK and various earthquakes.
The researchers believe the phenomenon may be explained by the fact male foetuses take longer to complete their early developmental stages, leaving them more vulnerable to sub-optimal conditions in the womb.
Sure. And we see much the same, tho’ stronger, in times of real stress like near famine. Male female ratio at conception stays the same. Girl ratio at birth soars. There’s selective abortion (not, perhaps, spontaneous as it’s being caused, but not consciously) going on. Even if it’s abortion by unthinking hormones rather than adult human action.
The argument deployed. Children born after a pregnancy at a time of stress are usually smaller. Assuming that the stress lasts for some time they’ll also be nutritionally deficient during childhood – the chances of stunting rise.
Male children who grow up runty lose out in the having grandchildren stakes. Female children, assuming that times aren’t so hard that the plumbing still works, will still have those grandchildren even if runty.
The aim of life is grandchildren. Thus, selective abortion of male foeti in times of stress. Why bother to invest in what won’t produce the point of the exercise? Clear it out and start again, better luck next time.
We’re really pretty sure this is true of famine and near. So, why not with other forms of stress?
BTW, this is also used as the reason for Downs rising with maternal age. It’s not eggs decaying. Rather, when there’s plenty of time for another conception why not clear out the near failure. But when this might well be the last one then why not carry on?