Personally, I didnt really notice it

, well, if someone had asked me "who carried around the baby" I wouldve said the woman, but other than that it didn't cross my mind. I personally don't think it makes too much of a difference, but after reading this I get what you mean, and I guess it would be nice to share the parenting duties with the father but I don't think its vital, and may not be worth the coding.
Also did anyone think that maybe its to stop you getting the mother constantly pregnant to try and get as many kids as possible? Maybe it's some kind of detterant or something.. I don't know, but in other games there's been things like that.
Also, about the requests for it in VV, i know its a bit off topic, but I'd have one father to multiple children (different mothers) especially when my tribe was low on people. I'm not sure if it would work in VV for that reason, but maybe, I don't know.. just a thought

Anyways, in conclusion, I don't think it's worth the hassle, no offence, if I've caused any, but I'm sure if the whole career thing is that much of a problem to you you can find some way around it.