It's interesting really.
Paternity has been a preoccupation of men for an awfully long time and is a large part of the various ways that we have been controlled and oppressed all over the world for as long as anyone can remember.
In the UK an exception to the gra is around inheriting titles. It does not override male primogeniture.
The person who grows the baby and births it, and is the one who can breastfeed it, that role, that activity is under attack from multiple angles. Surrogacy with the woman who carries the baby as a vessel only, if she has no genetic link to the child she is seen as totally unlinked to it (a very male view). Here motherhood as a label to be rejected. I wonder if that's due to the stereotypes around mothers in society.
The thing about how women are responsible for all the ills in society is multiplied up for mothers.
Yet again the problem is probably with the stereotypes, and rather than try and change things so mothers aren't put in such tiny boxes, vilified in various parts of the press, held up to impossible standards, and taken a dim view of in many workplaces, the easy thing to do is just opt out.