You would need the both of fatherhood and motherhood to address the biological needs to procreate, feeding, protecting, parenting and supporting the offspring. Men can't do breastfeeding, for an example. Men have to protect their pregnant women. The roles of fatherhood and motherhood are vital for child's natural development of sexual orientation and gender role. It's human nature.
I am not sure what SegBeg meant by the question of "Can men have it all." There were the accounts of single fathers, not to mention men have the option to adopt the child. In other words, men can have it all, but I wouldn't recommend it.
No one can "have it all" even men. There will always be an area in life that takes priority over another even if it's the wrong thing. A man (like a woman) can have a career and family but he will either miss out on a big portion of his children's childhood or he will have to deal with taking a lower paid or less dangerous job for his family. Women can't have it all as many people say, but neither can men. No one can. One thing will always be more important than another.