The Values and Beliefs update, done last month, found 92 percent of those surveyed said extramarital sex is wrong. Nearly 60 percent say sexual relationships between single people are acceptable, and slightly more than half see nothing wrong in having a baby outside of marriage.
The poll of 1,015 adults was conducted May 7-10, before the revelations that Sen. John Ensign, R-Nev., and South Carolina Gov. Mark Sanford, also a Republican, had adulterous affairs.
The poll found 2 percent of Republicans, 5 percent of independents and 10 percent of Democrats can accept adulterous relationships, and men at 8 percent are slightly more accepting than woman. But there is little age-based difference.
An earlier poll, taken in November 2007, suggests their adultery does not necessarily mean Sanford's and Ensign's political careers are over. Nearly half the respondents, 46 percent, said they would not mind much if a presidential candidate was known to have had an affair.
The poll had a margin of error of 3 percent.