I have very few here because I haven't seen many good entries in the genre, but I want to post this to bait you into sending me good examples! I also have not seen board books featuring same-gender parents--there are plenty of picture books, but nothing for the page eaters of the world that I've seen except Todd Parr in all his glorious incarnations.
This is a running list. Asterisks* denote family favorites. Links are Amazon affiliate/indie bookstore. Please send any suggestions to firstname.lastname@example.org or @drivelanddrool.
Last updated: July 2016
The Mommy Book (Amazon/Indiebound): Todd Parr’s crazy-color stick people discuss how some mommies like to cook, some like to order pizza, and celebrates individuality versus stereotyping. Follows the pattern set in The Daddy Book and The Family Book. Each deals only with its title role, so families with two mommies or two daddies are set.