Mark A. Yarhouse is professor and Dr. Arthur P. Rech and Mrs. Jean May Rech Endowed Chair in Psychology and director of the Sexual and Gender Identity Institute. He is author of Understanding Sexual Identity: A Resource for Youth Ministers,Understanding Gender Dysphoria: Navigating Transgender Issues in a Changing Culture, and Costly Obedience: Listening to and Learning from Celibate Gay Christians. D. A. Carson is the series editor of Questions for Restless Minds. He is professor emeritus of New Testament at Trinity Evangelical Divinity School, cofounder of The Gospel Coalition, and author of numerous books, including The God Who Is There: Finding Your Place in God's Story.