US opinion on abortion has shifted with, for the first time in nearly 15 years, a narrow 51-percent majority identifying themselves as "pro-life," according to a new Gallup poll published Friday.
The "pro-life," anti-abortion opinion has risen from 44 percent a year ago, while the number of Americans who described themselves as "pro-choice" fell from 50 percent a year ago to 42 percent now.
The results "represent a significant shift," said Gallup, which interviewed 1,015 adults from May 7-10.
For the middle ground poll, Gallup said 53 percent of Americans believe abortion should be legal under certain circumstances, about even from a year ago.
This opinion's high point came under Democrat president Bill Clinton in 1997 when 67 percent said abortion should be legal under certain circumstances.
By comparison, the extreme views on remain polarized, with 23 percent saying abortion should be barred under any circumstances, up from 17 percent a year ago, and 22 percent maintaining the action should be allowed in "most circumstances," down from 28 percent last year.
The change in opinion has come due to a distinct tightening of ranks among Republicans on the ethical, and bio-ethical, issues.
The percentage of Republicans calling themselves "pro-life" jumped 10 percent in the last year from 60 to 70 percent, as little change was registered among Democrats and those who lean Democratic.
The opinion shift has coincided with the positions taken by the administration of President Barack Obama, which opened the funding gates to organizations that sponsor abortion and revived stem cell research.
Marking the controversy has been the vocal protests to Obama's visit to the major Catholic university Notre Dame at the weekend.
The "pro-life" position among Catholics has risen seven points in the last year, to 52 percent, as Protestants have registered an eight point increase to 59 percent, Gallup found.
For the first time in a decade, more men are against abortion (54 percent) than women (49 percent).
Gallup said their maximum sampling error was plus or minus three percent.