When Gabrielle confronts Carlos about tampering with her birth control, he not only denies it -- he blames it on his dead mother!
Gaby tells John he might be the father and after an initial freak out, he wants to take responsibility, starting with having it out with Carlos! Gaby persuades him not to say anything, because the baby -- whoever the father ends up being -- will have a better life with Carlos. When Carlos sees John, he asks him to come be their gardener again. "You are practically family," he says.