Republican presidential candidate Rick Santorum on Tuesday claimed that Massachusetts schools promote gay families, but not heterosexual marriages.

Appearing on Boston Herald Live, Santorum lamented the increasing number of single parent households, which he linked to gay-inclusive books in schools and supposed school policies against books about families led by opposite-sex married couples.

“I know in the schools in Massachusetts, in the grade school, they teach – there are books in place that say 'Suzy has two moms.' It's okay to put a book that says ‘Suzy has two moms’ but you can't put a book in there saying that moms and dads and marriage is important and tell people how important it is to be married before you have children, then you're moralizing,” Santorum said. “It’s okay to say, ‘Suzy has two moms’ or ‘Johnny has two dads,” but you can’t say that marriage is an important part of having a stable and healthy economy.”

Santorum added that if elected president he would work to limit marriage to heterosexual couples because “strengthening the American family” is “important not just for a culture but it's important for education.”

(Related: Rick Santorum wants constitutional amendment banning gay marriage.)