As the mother of four, and also as a retired educator (teacher and administrator in public, private, and religious schools), I am concerned about allowing any kind of discrimination by child-placing agencies. There is ample evidence, anecdotal and scientific, that all kinds of families can thrive, as long as the parents are stable, loving, and physically and mentally able to care for a child. In general, issues such as religion (or lack thereof), marital status, level of education, sexual orientation, etc. are irrelevant as long as careful investigations are made as to the individual's (or couple's) overall ability to support a child, emotionally and intellectually as well as financially. Placing a child in a new family is an enormous responsibility and any agency, public or private, that is entrusted with such a duty should be able to carry it out without regard to the personal prejudices of its employees or sponsors.
I believe that the original wording of 42USC671 was published well over a decade ago and we know that society has changed greatly during that decade. The concept of civil rights is, however, included in the original text, and that has become more broadly understood over the years. Single parents, biracial families, and non-heterosexual parents are recognized by society for sucessfully raising happy, productive, and well-adjusted children. Their civil rights and those of the children are denied when discriminatory practices are allowed.