Have you met anyone recently named Nathan or Tamara? Perhaps not, because they're all so busy now being born. But you will.

Nathan, Tamara, Stacy, Alexander, Emily, Daniel and Hayley are rapidly rising to the top of the charts of the most popular given names in the English-speaking world, according to Leslie Alan Dunkling, who compiles such charts.

Dunkling, a radio producer at the British Broadcasting Corporation who has been studying names on the side for 10 years, is the author of "First Names First," It is an analysis of fashions in first names, by nationality, race, social class and year.

He will tell you that "Alice is either 75 years old or a baby," Darren, Sharon and Karen probably all had parents who watched "Bewitched" on British television, Shelley and Murray are Canadian, Willie and Willie Mae are black, Gloria is Jewish but Rachel, Leah and Naomi may not be and Johnathan's parents had limited education.

He can tell you what the most popular names have been from the Middle Ages, when Goldburga, Swetman, Godiva and Pancras were among them, to the present era of Jennifer, Michael, Amy and Jason.

But what he cannot tell you is why all you child's classmates have the same name you gave him, after so much effort to come up with something slightly distinctive.

"It's amazingly mysterious how these suggestions must be subtly implanted in the mind," he said. "You can ask 50 parents why they named their daughters Jennifer last year, and they will give you 35 different reasons - and I would be suspicious of all of them."

They might speak of its sound, the way it matches a particular last name remains that the name didn't even ap-of some old association - but the fact remains that the name didn't even appear, 25 years ago, on the popularity lists it heads now.

The strangest thing, he said, is that choosing a name is more "isolated" than other conscious acts of social behavior. "It's usually done by young parents in their 20s, who are familiar with the names in their own peer group but don't want to use them. They want to establish that this is a new generation. They have no experience of names in their child's generation - they don't know that until later, when their child gets to school."

In general, he said, whites prefer "safe" names while blacks value originality, "the upper classes have a horror of modern names," and if men's names are used for girls (Shirley, Beverly, Tracy), they cease to be given to boys.

There is a feminist influence against "Adam's rib" names (Roberta, Philippa, Davida) now, and a revival of selected Victorian names (but not including such Victorian favorites as Minnie, Agnes, Walter and Wilbur).

A popular person used to inspire the use of a name, he said, provided that name was not regarded as the exclusive property of one individual such as (Queen) Victoria or Winston (Churchill).

Now such inspirations are more likely to come from fictional characters - a television role, for instance, rather than the actor who performs it. But the exclusive property rule still operates - you don't hear of other Elivises or Farrahs, he said.

For those who still want to know what to name the baby, Dunkling has some suggestions.

The first is to give three names. "We've made it an unwritten law that each person gets a first name and a middle name, but there's no reason for that. A third doesn't cost extra, and will give the child more choice later."

Begin, he says, with something common, allowing the child to get through a period he will spend "with the crulest people there are - children. They think if a name is abnormal, the bearer of it must be, and pretty soon they convince the bearer himself of it," he said.

The second name could be something more unusual, perhaps an odd name from one's own family; and the third more fanciful still. Then if the child is going to be in some field "where he needs a trade name - say if he becomes a politician or an actor," he can adopt one of these.

Then the only danger is that you will have chosen a name which someone will kill instantly by associating it with undesirable conduct (Dunkling says Oscar Wilde and Adolf Hitler killed their respective names, and he's waiting to see if former President Nixon will yet do in Richard) or which is so popular that it will soon become dated.

Or that the neighbors will think of it, too.