As long as he lowered his zipper he has responsibilities.
And as long as she removed her panties she has responsibilities, too...especially if she knows she is not using a contraceptive,... she is aware she is taking a terrible risk.
like the saying goes, it takes two to tango.....
and of course, he has no right to demand she undergo a medical procedure against her will.....but he has a right to make his wishes known.
Its totally up to the women to decide and if she gives birth, she knows she is taking on even more responsibility