The old and often bitter debate over what causes homosexuality took an unexpected turn this week in the wake of comments by a leading conservative Christian theologian, who says fellow evangelicals should accept that science may one day prove homosexuals are born gay. "We sin against homosexuals by insisting that sexual temptation and attraction are predominately chosen," wrote the Rev. Albert Mohler, the influential president of Southern Baptist Theological Seminary. Mohler's position is a startling departure from years of insistence among fundamentalists that gay rights advocates are wrong when they say homosexuality is not something they choose....