WASHINGTON (AP) _ President Clinton pushed Saturday to ``make adoption a reality for America's most vulnerable children.'' But he and the first lady deferred any thought of adopting a child of their own until after their White House years.

Clinton made clear that while he believes adoption is not practical now for his own family, there are thousands of children in the foster care system who need to find ``permanent homes and families to love them.''

``The holidays we celebrate this month teach us that through faith and love we can truly repair the world,'' Clinton said in his weekly radio address. ``I can think of no better way to fulfill the promise of this season than to bring a child into a family and a family to a child.''

The president moved to double the adoption of children in foster care by the end of the century.

``No child should be trapped in the limbo of foster care, particularly when there are families with open arms waiting,'' the president said.

Clinton said there are now nearly 450,000 children in the nation's foster care system, and of these, some 100,000 will not return to their original homes.

Each year, at least two thirds of the foster-care children who will not return to their own homes are also not permanently placed elsewhere, the president said, forcing many to wait as long as three years.

Clinton ordered the Department of Health and Human Services to report back in 60 days on how best to increase adoptions, including the use of ``sensible financial incentives to help states improve adoption rates.''

``We will double the number of children we move from foster care to permanent homes, from 27,000 a year today to 54,000 a year by the year 2000,'' he said.

As for his personal plans, Clinton made clear through his staff he does not believe his duties as president permit him to become an adoptive father, at least not now.

First lady Hillary Rodham Clinton, who has been a strong advocate of adoption, said last spring that she and the president were considering adopting a child as a brother or sister for their 16-year-old daughter Chelsea.

But assistant White House press secretary Barry Toiv said the Clintons have decided that with their present responsibilities ``they would not be able to devote the time and attention a baby would need.''

They also think it would be unfair to bring an older child into the maelstrom of publicity that life in the White House has become, Toiv said.

``They believe parenthood is an enormous responsibility that can't be entered into lightly,'' Toiv said. ``They don't rule out adopting later in life, but they believe it wouldn't work in the White House.''

Joining Clinton and his wife in the Oval Office during the radio address was a ``remarkable group of children and parents, all of whom know firsthand the possibilities of adoption,'' the president said.

The children, sitting on the floor, formed a horseshoe around the president and first lady, who were seated before a fireplace filled with holiday poinsettias.

``There's so much mythology about adoption,'' said Fredrica Gray of Hartford, Conn., who adopted her son Michael, now six, when he was two months old. ``It's the greatest thing I've done in my whole, entire life.''

Lawrence Inglese, a retired, single parent from Tobyhanna, Penn., adopted his 15-year-old son Jason, two years ago. He told the president: ``Jason and I made eye contact and he knew I was his father and I knew he was my son.''

Also present were the families of Francis and Michael Bryant of Manhattan, Kan; Carolyn and Glen Borie of Philadelphia, and four Washington-area children, ages 7 to 15, who are awaiting adoption.