If you're referring to Max (Goofy's son) or even the duck trio (Donald's nephews whose parents have never even been referenced), it's my guess that Max's mom is dead and so are ducks parents. However, Disney wants to keep everything disturbingly cheerful, so they simply never mention it. It's been my assumption since I was 6 after my brother died. My eyes were opened to reality and I was a little miffed with Disney for avoiding the issue. As for PJ, Pete's son, he has a mom and a little sister (as seen in Goof Troop), but the folks have obviously split up which is just another subject Disney avoids in its cartoons.
Anyway, all sex is deliberately avoided because the absolute focus of any Disney project is not "true love" or "man and wife" but instead the purity of friendship... which more often than one can argue against is mind-bendingly ambiguous. I've said before, "Let it be and let it go."