Ronald Reagan and the Republican Party have embraced the defense of the "traditional American family" as one of their main tenets for 1980 but, beyond the broad rhetoric, the "pro-family" movement will confront politicians with some thorny and controversial proposals.

Take the Family Protection Act, an innocuous-sounding piece of legislation sponsored by the co-chairman of Ronald Reagan's campaign, Sen. Paul Laxalt. The act, Laxalt says, will promote "a new dawning of the family in American life."

It would also deny federal education money to states that do not allow prayer in public buildings, declare spankings to be constitutional and forbid federal attempts to change child-abuse laws. It would refuse legal-services aid for abortion, school desegregation, divorce or homosexual-rights cases and require federally-supported clinics to tell parents when their unmarried teen-agers obtain contraceptives.

While Reagan places "family" first in his litany of values for a new Republican consensus, and President Carter runs television ads of himself helping Amy with her homework, neither candidate has endorsed the bill. Nor has Rep. John Anderson, nor most congressmen and senators, despite paeans of praise for the family in political speeches from coast to coast.

But a growing "pro-family movement" encompassing conservative, religious, anti-abortion anti-feminist, anti-pornography and anti-homosexual groups with a combined membership of several million people, is promoting the act.

It is, says Connie Marshner, one of a new breed of savvy conservative organizers, "a standard which can be used to distinguish truly pro-family politicians from those who merely mouth pro-family rehetoric -- a useful distinction for the decade of family politics."

Marshner, head of the Family Policy Division of the Free Congress Foundation, works with groups like Phyllis Schlafly's Eagle Forum, Howard Phillips' Conservative Caucus, Paul Weyrich's Committee for the Survival of a Free Congress and Jerry Falwell's Moral Majority, which alone claims a half-million paying members.

This issue-orriented coalition, born partly from the fiery ranks of anti-ERA and anti-abortion movements, pays no attention to platitudes. "I look for specifics," Marshner said.

Other specifics of the act, which includes more than 35 provisions, would give local schools "authority over sex-intermingling in sports and other school activities"; would withhold federal funds from textbooks that "belittle the traditional role of women in society" and would deny federal courts jurisdiction over the issues of voluntary prayer in public buildings and teacher selection.

"The family is now facing social and political threats of such magnitude as to compel a political defense," Laxalt said in introducing the bill last fall. t"With just a little help -- just removing the governmental barriers and allowing the traditional family roles to reassert themselves -- I am convinced that we will see a renaissance of the family."

However, in an interview yesterday, Laxalt sounded somewhat less enthusiastic. "Rather than attempt to push it, I decided to let it simmer in the public mill," he said. "I've gotten a lot of constructive criticism. Questions have been raised about the constitutionality of certain provisions." q

Laxalt said he has not discussed the bill with Reagan. "It would be premature," he said. He disagrees with Marshner's view that it will be used as a standard to measure pro-family sentiments. "I don't think it will be part of any litmus test," he said.

The Nevada senator said he would introduce it in a modified form next year. However, conservatives are planning a move to attach some provisions as riders to appropriations bills this year.

The Republicans platform calls for unspecified "legislation protecting and defending the traditional American family against the ongoing erosion of its base in our society." Several among the act's more than 35 provisions are endorsed, including the replacement of education program funds with block grants and a plank saying teachers must have the right not to join the union.

In defense of housewives, the act would revive the pre-1973 Defense Department rule that required servicemen separated from their families to send home part of their pay. It would allow tax-deductions for contributions to a nonworking spouse's bank account.

Ironically, several of the goals of the "pro-family movement" coincide with feminist issues. The act would eliminate the "marriage tax" which penalizes married couples with two incomes and would allow corporations to deduct contributions to joint employe-employer day care centers.

Other provisions would deny food stamps to college students; give tax exemptions and credits to households which include a dependent person 65 or older -- a bid to encourage extended families -- and give the child care credit for expenses incurred in connection with charitable, civil, political or religious volunteer work.

In an interview with Conservative Digest, which featured the bill on its cover last month, Weyrich of the Committee for the Survival of a Free Congress predicted that "as pro-family groups become better educated as to who the friends and enemies of the family are, and as they become better educated in how to participate in the political process, a lot of congressmen who today thumb their noses at the whole notion of a pro-family coalition are going to be humbled."

While pro-family groups, discouraged with Carter's policies, would seem to be Reagan's natural constituency, he can't take them for granted. "Reagan is okay on ERA and pro-life but he is not terribly strong on the social issues," Marshner said. "We haven't been able to penetrate the wall of country club Republicans around him."

Will she vote for Reagan? "I might just skip the top line," she said. "We got enthusiastic for Jimmy Carter and we were burned. If we get enthusiastic about Reagan we could get burned again."