When parents separate, whether married or not, the best interest of the children will always be the most important factor when deciding on custody and visitation. Not all splits are amicable, which can make it difficult to come to an agreement. Getting along or finding a way to be civil with your ex, will be the best gift you could ever give your children. Don't put them in the middle of your relationship problems; it's not their fault you & your ex couldn't make it work.
A case is scheduled to be heard in Texas concerning mothers delivering children through the process of in vitro fertilization. It appears to be the first case of its kind in that it will involve a child custody dispute between the woman that delivered a pair of twins through this process, and the man that was the donor and thus might be considered the father of the child.