DAVIS, Calif. — IT’S been widely observed that in recent elections men have leaned Republican and women Democratic. A key element of that gender gap is often assumed to be a difference in attitudes to women’s reproductive rights. The perception that men and women have divergent views on abortion has persisted over time. The line popularized by Gloria Steinem that “if men could get pregnant, abortion would be a sacrament” proposes that a male-female divide over this social issue is more or less a biological given. The polling confounds such stereotypes. The General Social Survey, which has been tracking American...