STATE COLLEGE, Pa. - Martha Freeman got the bad news at lunch from her publisher and literary agent. Although "The Trouble With Babies" had received good reviews, the sales of her children's book about a young San Francisco girl were poor compared with the first title in her series, and the paperback rights would not be sold. But more stunning was the reason: A brief passage buried in the book about two gay fathers and their adopted son apparently had discouraged many librarians from buying the title. Although they had enthusiastically purchased Freeman's previous book, "The Trouble With Cats," the...