This is a minimum, and doesn't include possible pregnancy disability or complications, none of which can be foreseen, and which are not at all rare. Just Do Not. It's an effort that is pragmatically unreasonable to expect from most people. It's not just a coin toss, absent the question of who earns more, as to which parent will be the one to whom the baby, then small child has primary bonds. There's no instant separation there.
Birth is a process.
Following delivery, a rather traumatic first upheaval in the infant's life, the baby optimally needs to reassert a very secure attachment with one caregiver. Usually, that will be the natural mother, because right after birth, she's the one who is most attached herself to the baby, and the one who has the hormonal urges to hold the baby and breastfeed it. It's the way it is. That aside, there is just no denying how strongly most mothers of newborn infants feel compared with the fathers. I f men felt as strongly as women about their babies, however, we'd be hearing about the abusive ones beating up on women who didn't let them do the bulk of the baby holding and care at least as often as we hear of the violent ones who go berserk over relationship jealousy, or because she didn't cook dinner the way he wanted it.