Two couples with same sex families each would like a child of the opposite sex. They are very good friends possibly in love with each others partners. Very liberal, very candid, very sexual, in their 30s. They have discussed each others wish for another child and have joked that maybe if they swapped partners they would get what they want. One drunken night they forget their inhibitions and natural taboos and have sex with each others partners. This results in 2 pregnancies but when the babies are born they find that they have each just added to their same sex families. They contemplate adopting each others child and the problems that this will cause. We don't find out if this ever happens. At the end we find out that both babies are sired by their mutual single friend, who has left to travel the world with his girlfriend. Only he and the two mothers no the truth.