You know... I am not so sure they would be all that different. I am a true believer in equality... we are different but way more similar than we think or accept.. I've read a lot about how much of the differences we think there are are really not so.. like the myth that girls aren't good at maths/science/computers etc... And how women are supposedly better at raising kids... but you know here we do have a fair bit of equality.. we very often see househusbands and men taking a much more active role in caring for kids...
So for sure it's excruciatingly painful to give birth and I don't think that men would like that bit. but there's every reason to think they would do a fantastic job at being the primary caregiver to a child.. and I think they would adapt pretty well... We would see more women in higher roles... and more equality.. but I think we are heading that way anyway and as far as I see it it's a good thing.. good for kids that dads are more involved and good for women that there is more choice.