This is your false premise. Nothing about fairness requires the law to give someone additional rights to offset someone else’s intrinsic advantages. Neither men nor women have a “legal right to decide against the burden of a child.” If either has a child, they’re on the hook for it. The law doesn’t need to give men an additional legal right to “make up” for the fact that women can terminate a pregnancy by exercising their natural right to control their own pregnancies.