Roger Scruton on Sex: What in any of this requires heterosexuality?

I just finished Roger Scruton’s An Intelligent Person’s Guide to Philosophy (1996). I’d planned on summarizing and responding to each chapter in order. But I gotta jump to his chapter on sex.
Glenn Branch, an amazon.com reviewer, says that Scruton claims “a uniquely privileged moral status for heterosexual monogamy.” Thing is, in this chapter at [...]