At last night's reception for Faith Ryan Whittlesey, the White House assistant for public liaison, two of the town's most talked about gaps just couldn't be overlooked.

There was hardly breathing space--nevermind a gap--between White House chief of staff James Baker and CIA Director William Casey as they stood having a quiet, cordial conversation by the toy slot machine on the mantel in the office of Sen. Paul Laxalt (R-Nev.). Baker and Casey, according to statements they've made earlier, are at odds over how Carter briefing papers ended up in Reagan's 1980 presidential campaign.

When Casey walked away from the mantel, Baker had some quick conversations with acquaintances that touched on the controversy. Said one guest: "I got a letter today that said, 'Well, if the material never helped Carter, how was it going to help Reagan.' " Baker laughed quietly, said "that's good" and moved on.

Casey, meanwhile, had turned his attention to counseling an earnest young man on how to work his way up through the bureaucracy.

But there was another gap--the gender gap--that drew a lot of talk from the 75 people who milled around the senatorial spread of wine and cheese. And a subdivision of that gap is the reported chasm between some of the president's advisers and Whittlesley's office over her role and solutions to the widespread belief that women perceive Ronald Reagan as insensitive.

"The gender gap issue is like a tricked mirror at the amusement park. It makes you elongated," said Phyllis Schlafly, one of the leading opponents of the Equal Rights Amendment.

"I don't see it as a real threat. I asked my daughters at dinner the other night and they don't hear their friends at college talking about it," said Sen. Chic Hecht (R-Nev.) Lori Hecht, a senior at Tulane University, said, "Women are talking about different issues but they think President Reagan is doing a good job."

However, Baker said, the White House is giving the gender gap issue highest priority. Some polls show Reagan has the support of only 30 percent of American women, and one White House adviser has said such anti-Reagan sentiment could "swamp" Republicans in 1984.

"There would appear to be some degree of difference in the support the president receives from women than men," Baker said. "But the difference is no greater than in 1980. But that's no reason why you don't address the problem."

To counteract the reality or the perception, the White House has given deputy chief of staff Michael Deaver leadership of a council on women, a move that led to speculation that Whittlesley, only four months on the job and the person responsible for dealing with special-interest groups, including women, was being downgraded.

"There's no change in my position at all," said Whittlesley, a lawyer and former ambassador, who greeted most of the guests on a first-name basis. "Giving Mike Deaver that responsibility was an elevation to a Big Four concern. But lots of people are doing women in the White House. I never had issues, policy or legislation. I am the outreach person."

Baker added: "The Deaver thing is not in any way meant to downgrade Faith but to bring more resources into the picture."

And Reagan is doing fine, said Nancy Steorts, the chairman of the Consumer Product Safety Commission. "There have been some fine appointments of women. If there is a disappointment, it's that the women are not being visible and speaking out," she said.