I am going to throw my two cents into the hat here…
I am sorry but there is an agenda there.
I really do not think it is radical but I believe as SDDuuuude does. It should be up to the parent to decide when and where the engage the topic with the child.
To that point remember Rich your parents signed a consent form for you to attend sex ed class. We all had our parents do that. Hence the decision of when that subject was broached still belonged to the parent(s).
The next argument would be that the kids are probably hearing about these things anyway on the school yard. My nieces go to a pre-school where there were multiple “two mommies” scenarios and my sister was forced to make a decision to explain the situation but it is still up to her what explanation she is going to give.
The point is that she still had control over the situation. It is not up to our schools to indoctrinate one line of thinking or another.
So lets go onto the verbiage…
Why did it have to be a “two mommies” scenario as the OP said? There is no other explanation to this other than to introduce the idea of a homosexual family to the reader. Simply… that is an agenda.
But why bring sexual identity at all into this?
Why not simply say something like “a loving couple adopt a child”… Strip all sexual identity, hetro or homo, from the argument and leave “two loving people” in the story. Much more beautiful of an idea than the whole straight/gay thing and leaves the reader to interpret the situation as they want to.
Leave the decisive language for 10th grade when they are reading 1984 and other suggestive literature and have the maturity to deal with subjects for themselves after their parents have had first crack at the Bird and the Bees.