Parents must be on the same page, period. If you are properly prepared to have a child you should have had a discussion as to how the child will be raised. An obvious caveat here is that you cannot predict the future and know exactly what will happen when your child is born. But if you agree in principle on how to raise your child, you will be steps ahead.
My wife and I make an excellent team in a variety of different ways. We know each other well enough to be able to predict how one person would react in a given situation. We can order food for each other without even having to ask (yes, I typically order at restaurants). We have the same level of education. We have many of the same interests. We were best friends who got married. Yes, we are quite lucky in that regard.
And our son is the beneficiary of our good relationship as well. We agree on how to raise him, what he should be learning, how to react if he gets hurt or acts out. We are a united front which prevents him from being confused too much or being able to play one spouse versus the other. We are learning on a daily basis about how to raise him, but we are learning together. You must be able to rely on your spouse without exception. If we have to make a decision, we make it together even though one could make the decision and the other would agree. Raising a child is not easy, so having a partner by your side whom you trust and respect infinitely makes it that much easier.