The American baby was the number one topic at a March of Dimes fund-raising dinner at the Four Seasons Hotel last night, an evening top-heavy with administration members who'd been coaxed along by their wives. For this reason, Topic No. 2 was the president's proposed budget. But since the wives were in charge of the evening, they gave it their special touch: Caspar Weinberger, for example, was introduced as "that sweet secretary of defense."

That might amuse some on Capitol Hill, where Weinberger has been more of a stubborn secretary of defense about possible cuts in his $238.6 billion budget. "We're following a path that is inherently just, right and true," he said last night about his insistence that defense cuts--except for $8 billion of his own--would imperil the nation. Then he rushed out the door.

The babies came later. After a dinner of lamb chops, the 400 guests heard child specialist T. Berry Brazelton, the featured speaker, talk about how "fathers never diaper babies the same as mothers" and how small babies will always respond to the female voice before the male. There were also some baby films, which everyone ooohed over.

It was another Washington event that combined three crucial elements--charity people, corporate donors and big government names--into an evening that made everyone happy. Last year, Health and Human Services Secretary Richard Schweiker went to the March of Dimes, the foundation that raises money for research against birth defects, to start "Healthy Mothers, Healthy Babies," a prenatal care media campaign. The March of Dimes went to Cabinet wives for their names, and one of the wives asked Nancy Reynolds, a well-connected and well-known lobbyist and consultant, to be the chairman. The March of Dimes also asked corporate people for money--$5,000 for a table, or, in the case of Procter & Gamble, $30,000 to pay the costs of the dinner. The March of Dimes made $110,000.

And there you have it. As Dave Younkin, a March of Dimes executive, explained: "I'm not sure we could have gotten the corporations that are here tonight to just write checks for $5,000 if they didn't have the opportunity to come here, sit around the table and meet all these people they want to do business with."

Among the most popular of that genre was James Baker, the White House chief of staff, who only hung around for the cocktail hour. Here's what he said about Weinberger's $8 billion proposed cut: "The number he suggested is the maximum amount that the president feels can be safely pared from the budget." This did not knock people off their feet.

In another corner of the room was Schweiker, now in his last stretch as HHS secretary. One of his favorite memories is the time he went before the budget review board--composed of Office of Management and Budget Director David Stockman, presidential counselor Edwin Meese, and Baker--and made an impassioned plea to save some of his budget. "Halfway through," said Schweiker, "Dave Stockman took out his white handkerchief, waved it in the air, and said, 'I surrender.' "

Other Washington notables included: Agriculture Secretary John Block, who said that the $10 billion proposed to be sliced from his $45 billion budget is "tight" but "realistic"; Labor Secretary Ray Donovan, who said "if you can't laugh a lot in this town, you cry"; and Peatsy Hollings, the wife of Fritz, the undeclared Democratic presidential candidate. She went to yesterday's Redskins parade and stood in the rain. Her husband couldn't believe it.

"Fritz said," she said, " 'Were you born in the hospital--or the bleachers?' "

Also on the evening's agenda was a taped message supporting the healthy babies program from Nancy Reagan, whose image appeared on a giant screen in the ballroom. Joan Lunden, the cohost of ABC's "Good Morning America," sent a taped message, too. She couldn't come because she was, in the true spirit of the evening, pregnant.