Despite those positions, Mr. Ryan, who was picked over the weekend to be Mitt Romney’s vice-presidential running mate, has said he wants to focus on the nation’s looming debt crisis, not on social issues, in the coming campaign.

Democrats, hoping to win a large majority of female voters in November, assailed Mr. Ryan’s record on abortion rights and women’s health on Sunday.

In an interview with the conservative Weekly Standard in 2010, Mr. Ryan, an observant Roman Catholic, played down the possibility of a truce on social issues, which had been suggested by Gov. Mitch Daniels of Indiana, a Republican.

“I’m as pro-life as a person gets,” Mr. Ryan said then. “You’re not going to have a truce. Judges are going to come up. Issues come up, they’re unavoidable, and I’m never going to not vote pro-life.”

In nearly 14 years as a Republican congressman from Wisconsin, Mr. Ryan has not only voted for legislation that would cut off federal money for Planned Parenthood and the Title X family planning program, but also backed bills to establish criminal penalties for certain doctors who perform the procedure known as partial-birth abortion.

He is a co-sponsor of a bill that would define fetuses as people entitled to full legal protection, a proposal that has become the latest focus in the battles over abortion. The bill declares, “The life of each human being begins with fertilization, cloning, or its functional equivalent, irrespective of sex, health, function or disability, defect, stage of biological development, or condition of dependency, at which time every human being shall have all the legal and constitutional attributes and privileges of personhood.”

The concept of personhood is a fundamental tenet of the anti-abortion movement, and under this definition, abortion and some forms of birth control could be construed as murder.

Like most Republicans, Mr. Ryan has strenuously opposed the new health care lawchampioned by President Obama. He has criticized Mr. Obama’s efforts to guarantee free insurance coverage of contraceptives for women, including those employed by Roman Catholic hospitals, universities and social service agencies.

“The contraceptive mandate is an affront to religious liberty,” Mr. Ryan has said.

“If the president is willing to trample on our constitutional rights in a difficult election year, imagine what he will do in implementing the rest of this law, after he doesn’t have to face the voters again, if he gets re-elected,” Mr. Ryan said in February on NBC’s “Meet the Press.”

David Axelrod, a top strategist for the Obama campaign, described Mr. Ryan on Sunday as “a right-wing ideologue.”

“Congressman Ryan would ban a woman’s right to choose, even in cases of rape and incest,” Mr. Axelrod said on CNN’s “State of the Union.” “So he is quite extreme. Good, good person, you know, genial person, but his views are quite harsh.”

Mr. Ryan, speaking on gay rights, has said, “I believe fundamentally that marriage is between a man and a woman.”

He voted in 2006 for a constitutional amendment to ban same-sex marriage. And, as he said recently, he supported an amendment to the Wisconsin Constitution, approved in 2006, that denies official recognition to same-sex marriage.

“Only a marriage between one man and one woman shall be valid or recognized as a marriage in this state,” the amendment says. “A legal status identical or substantially similar to that of marriage for unmarried individuals shall not be valid or recognized in this state.”

Mr. Ryan voted in 2009 against a bill that would expand federal hate crime laws to cover offenses based on a victim’s sexual orientation or gender identity.

Nevertheless, in a break with many members of his party, Mr. Ryan voted in 2007 for a bill that would prohibit employment discrimination based on sexual orientation.

R. Clarke Cooper of the Log Cabin Republicans, a gay rights group, said, “Congressman Ryan’s vote in favor of the Employment Nondiscrimination Act and his consistent willingness to engage with Log Cabin on a range of issues speaks to his record as a fair-minded policy maker.”

An avid hunter, Mr. Ryan supports gun owners’ rights and voted for legislation that would generally bar people from suing gun manufacturers for damages caused by misuse of their products.

Appearing on C-Span shortly after he was first elected to Congress in 1998, Mr. Ryan said, “I do not think that more gun control laws are going to solve our crime problems.” He added, “Gun control is not crime control.”

Noting that he had lived on Capitol Hill, Mr. Ryan said: “I’ve been mugged before. I’ve heard the gunshots. This city has perhaps the most stringent gun control laws in any city in the country. Yet it has perhaps the greatest crime problems with firearms.”

He voted in 1999 against a proposal that would have established much more stringent requirements for background checks on people buying firearms at gun shows. He voted last year for a gun-rights bill under which a permit to carry a concealed firearm in one state would be valid in almost every other state.

Mr. Ryan also voted last year for a bill stipulating that no federal money could be made available to NPR.

And he has supported a ban on flag burning, voting for a constitutional amendment empowering Congress to outlaw the practice.