Yesterday would have been a traditionally cheerful Christmas celebration, filled with gift-giving and family fun at the Northwest Washington home of Moorhead C. Kennedy Jr. His wife, Louisa, and four sons were there. Presents were beneath the Christmas tree.

But Kennedy, 49, could not be with them. He is among the Americans held hostage at the U.S. Embassy in Tehran. His family has tried to send him a warm Christmas message, but does not know if it arrived.

"It gives us actually more of a reason to celebrate Christmas. We have more things to wish for," his 18-year-old son Andrew said on Christmas Eve. "We try to think about how wonderful it could be if my father were here. At least, we know at the same time we're thinking about him, he's thinking about us."

Kennedy had only been in Tehran for a few weeks on a special assignment for the State Department when the embassy takeover occurred.

"He was supposed to come back right before Christmas," Andrew, a student at Middlebury College in Vermont, noted. Now, his family can only hope the siege by Iranian militants soon will end and he will come home again.

Membes of the Kennedy household have joined with other hostages' families in ceremonies symbolizing their hopes. Fourteen-year-old Duncan Kennedy helped lay a red and green boxwood wreath at the Lincoln Memorial during a silent vigil earlier this month. The family's Christmas plans included attending a special religious service for the hostages' relatives and well-wishers.

"We're trying to spend it as cheerfully as possible. We always have a reservation in mind. We try not to think about it too often," his son Andrew said."We're certainly not disregarding everything that Christmas stands for."