No, they can easily cut you out and you pay child support and extra's for the next 18+ years. Adopt or get a surrogate.

OP, do you not plan to have kids of your own?

Why were you browsing such a site in the first place? Would you like to coparent?

I know a love story that started this way! The guy was arranging to be a donor for a lesbian couple and their friend jokingly asked if he would consider her too, and the rest is history. They are married and have two boys together. He also went thru with the first donation, and it’s a little weird (they all know each other and what the relationship is) but otherwise I guess it’s not much more weird than all kinds of blended families?