Stick with Science.

All the insecure gay people who need schoolchildren to affirm their families probably want to keep their own beliefs out of the classroom.  Because there is likely gonna be some hurt feelings when an educated child tells yours that they indeed do have a "daddy" out there somewhere who helped create them.

Donors aren't daddies, but they are a natural part of creating a child.  Ditto if a surrogate mother carried them...

Every child is conceived by a man and a woman, no matter how the adoptive parent identifies (gay women can call themselves Dad's too, if you're into that) or how much they want to pretend away science.  Will a little boy raised by two women want to grow up to be a present father in the home raising his children, or we he just see his role as donating sperm and done?

That's really something intimate you need to discuss within your family.  Please don't make a big issue that other families have to deny science to accept your family.  We do!  Accept you!  But many of us are not willing to underplay the importance of a mother and a father in creating that formation.  Why is it so hard for some gay people to accept people have other values and beliefs?  

Best... keep this stuff out of the grade schools.  Invite as playmates those children from families sympathetic to your situation, or those who are secure enough in their family formations not to intrude upon a child's understanding of science and reality?  It's really sad for the children that the adults need to push this issue for attention.