“This is a sharp change from the late 1970s, when seniors were substantially more likely than younger age groups to want abortion to be illegal,” she wrote.

Young adults ages 18-29 who once were among the top supporters of legalized abortion now are its leading opponents when compared to other age groups, according to a Gallup analysis of survey trends since the 1973 landmark Roe v. Wade decision.

Gallup examined the views on abortion of four age groups and found that in an average of polls from 2005-09, 23 percent of those ages 18-29 believed that abortion should be “illegal in all circumstances,” an increase of five points from the period of 1975-79 and nine points from 1990-94. The 23 percent figure tops all age groups, ahead of those ages 65 and older (21 percent) and those ages 30-49 and 50-64 (both of which are at 17 percent).

Opposition to abortion, Gallup said in its analysis, is “growing fastest among young adults.” Gallup’s Lydia Saad wrote that “18- to 29-year-olds are now roughly tied with seniors as the most likely of all age groups to hold this position on abortion — although all four groups are fairly close in their views.

“This is a sharp change from the late 1970s, when seniors were substantially more likely than younger age groups to want abortion to be illegal,” she wrote.