Well, no. Child support is only relevant if the child is actually born. In that case, there is a kid.You seem to all be ignoring the point that abortion is the other option. There is no kid yet. If she decides to go through with it, it's her decision, but she needs to realize that, since she's breaking the agreement they had, he's absolved of the responsibility.
This whole question takes as given that a child exists. We're all trying to answer a particular question: if all this stuff happens and a child ends up being born anyhow, what should happen?
In the case of an adoption, the woman would have to demonstrate that she has the resources to raise the child on her own. If she doesn't, then the adoption wouldn't happen.Would it be nice if he stuck around anyway, or helped out at least? Sure. Should he be forced to? No.
Think of it this way: She decides she wants kids, but can't biologically have them, so she chooses to adopt. They had already agreed never to have kids because neither wanted them. Should he now be forced to help pay for or care for the adopted kid, or should he be able to walk away?
In that case, the needs of the child are considered. Why don't you want the needs of the child to be considered in the other case?