Once these arguments have been dealt with, though, many people will want to explore faith from a more positive, more assertive perspective - for example, exploring Scripture or prayer & spirituality from a gay perspective.
Horner's "Johnathan loved David" is a well-known & widely recommended look at same- sex relationships in the Bible. "Take back the Word" (ed Robert Goss) does not look at specfically gay or lesbian passages in Scripture, but rather looks at other well-known passages and offers interpretations from a queer perspective.
This is precisely what James Alison does. He is a former Dominican priest and lecturer in theology, who is now an independent theologian, writing and lecturing to groups around the world. He does not write only about gay issues, but in a notable set of three books, he writes specifically "theology from a gay (male) perspective" - not gay theology. These books, all much admired and commended, present sound, tightly reasoned theology, but in an informal, non-academic style. These three books, best read in sequence, are "Faith Beyond Resentment: Fragments Catholic and Gay", "On Being Liked", and "Undergoing God."
For those willing to work with a more academic treatment, a book I found immensely useful is Elisabeth Stuart's "Gay & Lesbian Theology: Repetitions with Critical Differences." The value of this book for me was in its concise summary of the development of different approaches to theology from an LGBT perspective, from its early beginnings, through liberation theology, queer theology, indecent theology and beyond. In summarising the key ideas, she also introduces the reader to some of the important thinkers and writers presenting these new strands in theological thinking.