Now, something I would consider if they disagree: Either party may declare their lack of desire for the fetus. Doing so terminates all rights and responsibilities but comes at a cost:
For the man: He must provide half the all-in cost of an abortion 1 week from the point of the notice, perhaps with a minimum amount of the actual cost of an abortion. This must be provided in certified funds at the time of the notice. She is not obligated to have an abortion, however--if she does not she is considered the only parent.
For the woman: She is not allowed an abortion for non-medical reasons. She gets her medical bills through delivery covered. He is considered the only parent. (In effect, she becomes a surrogate.)
The last part would pose a serious threat to the principle of bodily sovereignty that is the foundation of all rights and secular ethics. No person have any legal rights to determine what another person does with their body or whether or not they have any type of medical procedure, unless the person is psychologically incapable of conveying their own will at the time. There should be no legal contract that allows a person to forfeit that right to exert their own will over their own body at any time. Current surrogacy contract law is potentially problematic. Some of it does seem to give dna donors rights to dictate whether or not a surrogate can get an abortion.
However, I suspect that even there the surrogate cannot actually be forced to have or not have an abortion, but rather they merely can be sued for the costs incurred by the other party.
A father relinquishing any rights in exchange for a lack of financial responsibility is less problematic because it does not relate to the issue of bodily sovereignty.
