I think there is a material difference between a risk that transpires, and the intentional concealment of the risk. In my view the morality of the situation is as follows. The man who claims to be sterile or to have had a vasectomy, or the woman who clames to be on the pill or to be sterile is the party primarily responsible for any ensuing pregnancy and birth. The former should not only be liable for support for both the child and the woman, but also for damages (as in any other fraud case), and the latter should net be entitled to support for the child or herself. I can't see a claim for damages in the latter case. There is no physical trauma to the man. The fraudulent man should not be entitled to access, but the defrauded man should, if he wants it.