T. A. Gardner
Thread Killer
Men had a say at least at two stages: (1) whether to have sex, and (2) whether to use contraception. Women have it at three stages, with the additional option to have an abortion. Perhaps a fair way to handle it is that the man gets asked what he wants. If he wants her to have an abortion and she does, he pays for half of that. If he wants her not to have an abortion and she does have one, he doesn't pay anything. If he wants her not to have an abortion and she doesn't, he pays for half the child's support. And if he wants her to have an abortion and she doesn't, he pays for 2/5 the child's support (since he had two stages at which to prevent the creation of that child, and the woman had 3).
In standard contract law, this would be an agreement between two parties. At all stages, both have a say. So, if she gets pregnant, both have to decide how to proceed.
If she wants the child and he doesn't, she's responsible and he has no further say.
If he wants the child and she doesn't, she carries it to term, he pays for that after which she has no further say.
If they both want the child, then they share the expenses of raising it.
If neither want the child, then they pay half each for an abortion.
The man gets equal say in that equation from conception to age of majority. Anything else is patently unfair and unequal.