LOS ANGELES, JULY 6 -- The J. Paul Getty Museum in Malibu has removed its prized Greek "kouros" for study because of new doubts about the authenticity of the statue.

The 6-foot-8-inch marble sculpture of a young man, thought to date from the 6th century B.C., is one of the museum's three most celebrated Greek antiquities, along with a monumental marble "Aphrodite" and a bronze "Victorious Athlete."

The museum purchased the kouros in 1985, after 14 months of study, for an undisclosed price from a private collector through an unidentified Swiss dealer. The Getty put it on view in 1986 after additional study and conservation. But the recent discovery of a marble torso that is generally regarded as a forgery or a modern copy has raised new questions about the Getty statue, museum curator Marion True said in a prepared statement today.

The torso, which came to the museum's attention in April, differs from the kouros in surface and general appearance, but is made of similar marble, "possibly from the same quarry," and shows "subtle similarities of style and detail," True said.

The kouros was removed from the antiquities gallery today, and the two pieces will be studied during the coming months, Museum Director John Walsh said in a telephone interview.

"Naturally, we will be very disappointed if our new studies lead to the conclusion that the museum's kouros is not an authentic work," Walsh said, "but it's most important that we try to discover the truth about the two statues.

"These cases arise in the field, and they occur at this museum as they do in other museums that collect antiquities. The main thing is to determine the truth and make it known," he said.

The situation would seem to be an embarrassment to the wealthy museum, but Walsh said it is more of "a puzzle, though a very prominent puzzle."

Critics have commented on the statue's archaic-style smile and the fact that its stylized hair, eyes and hands contrast with more realistic features. In a study published by the museum, True acknowledged that the kouros had "unusual stylistic features," Walsh said. Some anatomical forms on the marble appear quite "old-fashioned" while others are more "up to date," he said. "That's something that has to be explained."

The new torso has sufficient similarities in the execution of the anatomy to cause the museum to rethink its earlier conclusion that the kouros is genuine, Walsh said. He declined to comment on the museum's recourse if the statue is proved inauthentic. "That would be between us and the seller," he said.