Throughout history women as young as 11-12 have had babies, that was very dangereous for both the women and the babies. These 11-12 year olds are still kids but in certain cases nature decided they were mature enough to be pregnant.
Society try to improve lives, that's why it was totally normal to prevent sex with 10-12 year olds, to prevent the death of these girls and their infants.
But then society continued raising the age, 13,14,15,16,17,18,19,20,21 ...
It is ridiculous to imagine that a 16-17 old woman have a higher risk than let's say 22 year old. Girls once they are 14, they reach often the last growth phase, they look as tall as an adult woman, and often look as if they are 18-20 year olds.
What is more ridiculous is the amount of men jailed for having consensual sex with under 18-21 women, even big celebrities are hunted down for having a sexual relation with under 18 year olds. The sad part is that often it's the girls that initiate the relation, usually a honeytrap.
Something that sounds very normal from a biological and evolutionary point of view, have been made illegal by society.
And yet, women are allowed abortion, or killing embryos, something that nature, biology and evolution would never allow, yet it is allowed by the society.