FERTILITY-DECLINE REPORTS CONTESTED : STUDIES SAY SPERM COUNTS HIGHER TODAY, HIGHEST IN NEW YORK CITY.

Byline: Gina Kolata The New York Times

The news was dire, the possibilities catastrophic. Men the world over, several widely publicized studies reported, are losing sperm, with counts declining drastically over the past few decades. If the trend continues, some researchers warned, there will be no human population in a couple of centuries.

But two careful studies have found that men in several U.S. cities might have more sperm today than men had 20 years ago. Perhaps just as unexpected, men in New York City, for unknown reasons, consistently have the highest sperm counts of all - more than 50 percent higher than the sperm counts of men in Los Angeles, for example.

The papers are in the May issue of the journal Fertility and Sterility, and researchers say they provide a much-needed balance to the previous alarming studies. The detailed results, made available for the first time, took even seasoned researchers by surprise.

Dr. Stephen Safe, a toxicologist at Texas A&M University, said Friday in a telephone interview that he heard the data at a closed meeting in Houston last fall. Those at the meeting had ``absolutely no idea'' why New Yorkers should have so many sperm, he said.

Dr. Larry L. Lipshultz, who directs male-infertility research at Baylor College of Medicine in Houston, said he had been ``very surprised'' by the New York data. Lipshultz organized the Houston meeting.

The broader issue, an abrupt turnabout in the story of precipitously declining sperm counts, may seem confusing, some researchers said, but it does not mean that science itself is inconsistent.

Sperm counts could indeed be declining in some areas of the world. But as more data on sperm counts have come to light, Lipshultz said, ``we can fairly comfortably say that there does not appear to be a worldwide trend.''

In one of the new papers, Dr. Harry Fisch of Columbia-Presbyterian Medical Center in New York and his colleagues examined data from semen analyses of 1,283 men who donated semen to sperm banks before having vasectomies. The sperm banks were in New York City, Los Angeles and Roseville, Minn.

In looking at data from the period 1970 to 1994, Fisch found ``a slight but significant increase'' in sperm counts but no change in sperm motility or semen volume, two other parameters of fertility.

Fisch also found that New York men had much higher sperm counts than men from the other two cities, with an average of 131.5 million sperm per milliliter of semen. Men in Minnesota had 100.8 million sperm per milliliter of semen, and those in Los Angeles had 72.7 million.

Fisch's conclusions that sperm counts are not declining and that New York sperm counts have always been high became public last month, but Fisch declined to release any details of his studies before his paper was published.

In a second paper published in the same issue of the journal, Dr. C. Alvin Paulsen of the University of Washington found no decline in sperm counts or semen quality in samples collected from 1972 to 1993 from 510 healthy young Seattle men.

The sperm counts in Paulsen's study cannot be directly compared with those in Fisch's study because the men were selected differently. Sperm counts vary with factors such as age and the duration of abstinence from sexual activity before a man provides a semen sample.

Paulsen found that sperm counts remained almost identical over the 21 years, going from an average of 46.5 million sperm per milliliter of semen in 1972 to 52 million in 1993.