As debates about gay marriage continue to rage, Michael Lowenthal, a creative-writing instructor and author of the acclaimed 2007 novel “Charity Girl,’’ enters the ring with a focused, mostly poignant examination of a gay couple’s struggle to father a child via a surrogate mother.

On the surface, Pat and Stu are a bit of an odd couple. Pat, a poetry major who now writes textbooks, is steady, reliable, and cerebral regarding love and romance (his sexual awakening was even well thought-out: “A feature and its opposite could equally entice me because, in the end, it wasn’t boys’ particulars that moved me but their fundamental maleness.”). Stu is by far the more flamboyant and carefree of the two, a brash, extroverted airline pilot with a history of reckless promiscuity in New York City.