I fail to see the problem here.
The little boys - being shunned and hated by their lesbian mother, and without ANY real male role model in the home - will grow up to be hairdressers and interior decorators, and link up with their half brother(s) when they're of age.
The girls - having little else for a role model in their lives other than their raging, man-hating mother - will grow up to be truck drivers or bull riders, with an insatiable taste for tuna, because that has been the breadth of the definition of "normal" throughout their formative years.
It's not like there's gonna be any "uncle daddy" or "aunt mommy" stuff rising in those poor children's messed up, Bizzarro World lives.