His principal areas of expertise include problems associated with anxiety, depression, sexual dysfunction, sexuality and aging, and marital concerns. He is board certified in medical psychology, psychopharmacology, and sex therapy. He serves as the President of the Academy of Medical Psychology and of the American Board of Medical Psychology. He has co-authored A Celebration of Sex After 50 with his wife Carolyn and Doug Rosenau and Purity & Passion: Authentic Male Sexuality with Rick Ghent