Again, yes.....they can be interchangeable......by that I mean the roles they provide.....not physical aspects of their bodies or sexual functions!!!The roles of 'MOTHER AND FATHER' are not interchangeable...get it???
There are plenty of little girls who are being raised by their Dads.......their female role models are their grandmothers, aunts, older cousins and female friends of their dad's.
There are plenty of little boys who are being raised by their Moms.......their male role models are their grandfathers, uncles, older cousins and male friends of their mom's.
These kids turn our normal, healthy and happy.....grow-up to be successful, get married to the opposite-sex and raise children of their own......why do you need to define roles as stereotypical for men and women?