In short, it gives an example of a role model for both sexes, and 'role' means just that...being the role of a father, or of a mother, amoung other 'roles'. I am sure that there is much to gain in most family situations if they are loving, but it is not an error to value the most ideal situation.
thats just your opinion though, how is it "ideal"? there is not one shred of evidence that shows you need a mother and a father, there is evidence that 1 or more loving people are what you need and you can figure the roles out from any male or female person
your list has nothing to do with having parents of different sexes, just an observent kid with good values and you just need someone with good values to raise them, heck a grandfather or grandmother only could teach those
this just seems like you are making an argument from tradition, nothing more
as i've come to realize though, all traditions are wrong