PROSECUTORS SEEKING CLINTON DNA FOR TEST.

Byline: James Bennet and Don Van Natta Jr. The New York Times

In a sign that prosecutors are dissatisfied with President Clinton's limited admission of an intimate relationship with Monica Lewinsky, they demanded Wednesday that he provide a sample of his genetic material to establish forensic proof that the relationship was sexual.

The move strongly suggests that the FBI crime lab has determined that a dress turned over to prosecutors by Lewinsky contained DNA from semen. One person familiar with the findings said the lab technicians had found semen on the dress. Prosecutors are trying to determine whether Clinton stained the dress in a sexual encounter with Lewinsky, a former White House intern.

The request by Independent Counsel Kenneth Starr came on Clinton's 52nd birthday, which he marked privately with his family during a vacation on Martha's Vineyard. It signaled that prosecutors do not plan to soften their aggressive tactics after Clinton's admission to a grand jury Monday that he had ``inappropriate intimate physical contact'' with Lewinsky in the White House.

Clinton's team had believed that the results of testing on the dress were mooted by the president's admission, as well as by a brief speech he gave Monday night calling the relationship ``not appropriate.''

White House press secretary Mike McCurry said any sample turned over to the FBI would be obtained from the Bethesda Naval Hospital, where Clinton undergoes annual physicals and where supplies of his blood are stored.

It was not immediately known how Clinton's lawyers would respond to the request. It came a day before Lewinsky, who was said by friends to feel hurt by the president's terse public description of their relationship, is scheduled to appear for a second time before the grand jury here.

Starr's request suggested that he is determined to learn what specific type of sex Clinton and Lewinsky had. But such an effort could work to the president's political benefit as Congress weighs conducting impeachment hearings, some of his advisers believe. They think it could make prosecutors appear sex-obsessed, even as most Americans tell pollsters that they already know more than they would like about lies, betrayal and sexual indiscretion at the White House.

Starr dissatisfied

But Starr is clearly dissatisfied with the president's testimony. Clinton refused to give prosecutors a detailed description of his sexual contact with Lewinsky, after reading a statement admitting the affair at the beginning of his four-hour testimony.

Starr has been seeking to determine whether Clinton committed perjury in January, when he denied any sexual relationship with Lewinsky during a deposition in the Paula Jones sexual misconduct suit.

In his testimony Monday, Clinton argued that the type of sex he had with Lewinsky did not fit the definition of sex used by the Jones lawyers. Although he rebuffed prosecutors' questions about his sexual contact with Lewinsky, he did answer a series of questions about what types of sex he considered to be covered by that definition, one Clinton adviser said Wednesday. The president said that oral sex, among other acts, was not covered by the definition, the adviser said.

But the adviser to Clinton said the president did not acknowledge having oral sex or any other type of specific sexual contact with Lewinsky, instead referring prosecutors back to his initial statement.

``Over and over, he said, `I've already said that it was improper,' '' said the adviser, who spoke on condition of anonymity.

Because Starr has asked the president for a DNA sample, it is highly unlikely that he had not been told what was found on the dress.

But Starr chose to wait to ask for a sample of the president's genetic material until after Clinton completed his grand jury testimony. Law enforcement officials dismissed the possibility that Starr would have asked the president for a sample in an attempt to ``bluff'' him.

A careful vagueness about his encounters with Lewinsky is central to the president's legal and political strategy, his advisers say, since it could help deflect a possible perjury charge while also walling off seamy details from an already queasy public. Clinton was even more vague in his four-minute address Monday night than in his testimony.

Huge TV audience

That speech was watched by 67.6 million people, Nielsen Media Research said Wednesday. Some 53 million viewers watched his far-longer State of the Union message, delivered shortly after Clinton was first accused of having an affair with Lewinsky and covering it up.

Clinton advisers have said that Clinton answered every question put to him that did not deal with sex. That position is also central to the president's political defense: If Starr demands further testimony, the president's team would like to be able to argue that prosecutors are intent on grilling him only about intimate matters. ``We want to make the argument that Starr's investigation is just about sex,'' the adviser said.

David Kendall, Clinton's private attorney, did not agree to extend his testimony more than a few minutes beyond the four-hour time limit, even though prosecutors had more questions. Starr said he might subpoena Clinton for further testimony.

The White House would not confirm the request from Starr's office. It released a two-sentence statement: ``On Monday night the president acknowledged an improper relationship and apologized for that. The president also said it's time to reclaim his privacy, and we will respect that by not commenting on every leak generated by this investigation.''