the probable reason is the stressed out condition of the modern mother whose stress hormones are providing the "soup" in which the new baby is growing
ultra processed food is the new version of smoking in terms of health.
more women are overweight
they are also having children older
they get less sunlight and are lower in vit d
they are more prone to glucose tolerance issues (so my wife the nurse says).
they are under enormous financial pressure which stresses them out
we also know , due to bad food and overwight, men produce less then 50 % as many sperm as 40 years ago and there are more abnormal sperm.
the solution is , of course "personal responsibility" to get yourself fit and change your nutrition , exercise, do meditation and walks in nature to reduce stress hormones, do yoga and on and on.
but thats a dirty word to many, so its easier to just have a sick child and then complain.
remember the golden rule
you dont get what you want
you get what you are