My wife, Marilyn McCord Adams, who has died of cancer aged 73, was the first woman, and the first American, to hold the regius professorship of divinity at Oxford. In that capacity, during the years 2004-09, and as a delegate to the General Synod of the Church of England, she was widely known for her forceful defence of loyal same-sex partnerships as legitimate expressions of Christian love.

Her convictions on that subject were formed in Los Angeles in the 1980s. While teaching philosophy at UCLA (the University of California at Los Angeles), and publishing a definitive two-volume study of the philosophy of William Ockham, Marilyn was also preparing for ordination as a priest in the Episcopal church. As part of that process she was assisting in ministry at a church in Hollywood, where gay men, in the first terrible years of the Aids crisis, were seeking spiritual support. She was deeply moved by their need, and no less by the depth of their love and loyalty towards each other.

During those years, also, she turned her interests more and more towards Christian theology and religious ministry. She never gave up the commitment to philosophical reasoning formed during her years of study at the University of Illinois in Urbana (BA 1964) and Cornell University (PhD 1967). But the topic that most gripped her, and most inspired her intellectual work through the rest of her life was the theological problem of evil. She developed a distinctive approach that had a major impact on discussion of that problem. In Horrendous Evils and the Goodness of God (2000), she does not try to answer the question, “Why did God permit all the evils that we know about?” Rather she asks, “What can God do to make our existence a great good to us, without trivialising the horrendous evils that we know about?” And she gives an answer in terms of friendship offered by God, which she saw in the story of Jesus, and also saw echoed in the lives of gay people loving each other in the face of Aids.

Born in a suburb of Chicago, to William McCord, a pipeline engineer, and his wife, Wilmah (nee Brown), a schoolteacher, Marilyn grew up in small towns in rural east-central Illinois. But she loved university towns and large cities. Many of her former students and their families form the largest part of a devoted extended family that survives her.

Marilyn is also survived by her brother, Bill.