It seems kind of dumb, of course the role can be replaced. Its not like a father today is doing anything super specific to child survival. Just feed, change and play with the kid, obviously anyone of any sex can do these things.
I certainly don't see my role with my children as just a babysitter. The partnership with my wife to raise our family is a complex and rich engagement between our strengths and weaknesses to aid in our kids development, not only physically, but also mentally and emotionally among other aspects.
Actually, different people have different strengths.