Another unique situation that gay parents might find themselves in, is when one of the parents was in a straight relationship and came out before or after a divorce. In most cases, it is advisable to make sure that there would not be any problems with parental rights before such a parent comes out. In this situation, the children had two heterosexual parents, and suddenly, they have a gay and a straight parent (with possible gay and straight step-parents).
At what point would it be necessary to tell the children what is going on? A few of my clients received advice from professionals that it would be better to wait until the children know the difference between homo- and heterosexual relationships. This advice mostly came from heterosexual therapists. The rationale behind this argument is that homosexuality is something strange that should be avoided in conversations with children. In my experience, it is a big mistake to keep this from your children for an extended time.