Legal Question in Civil Litigation in California

Your question presumes that only a child's parents can be guilty of abusing her. That's not true. Whether the accused is the victim's parent matters, but it's not an essential element of child abuse. People are convicted of abusing other people's children all the time.

You haven't told us enough to evaluate the evidence against you. It could be very strong or very weak for all we know. But the fact that you don't have kids isn't the rock-solid defense you seem to think it is.

Good luck.