Preston Sprinkle holds to a historic Christian view of marriage and sexuality. In his latest book he takes up some common questions and arguments in favor of same-sex marriage, and gently explains why he doesn't find them convincing. I think Preston Sprinkle sometimes tries just a little too hard to find common ground with those who wish to revise thousands of years of Christian moral teaching, but his scholarship is thorough and he does a good job of answering all the common arguments (and most of the uncommon ones) that you might encounter. There are 21 chapters, but they are short.