That is almost double the current estimate of 10 million men, the senior author said in an interview.

He was senior author and co-author in about 50 scientific publications, and published a number of books.

Dr. Theriault is the senior author of a paper about the trial, which he said had been accepted for publication in a medical journal.

From 1949 to 1990, he wrote, as senior author, 356 papers on all aspects of neurosurgery.

She was the senior author of a 2010 study that detected autism "clusters" in California associated with high levels of education among the children's parents.

She was the senior author of an Army field manual on terrain intelligence.

He is also the principal investigator and senior author of the largest national study ever conducted on social distance.

Dr. Nilsson is the senior author on the new report, which appears in the current issue of the journal Nature.

Astrid E. Fletcher, the senior author of the study, said the findings suggested a need for fresh thinking.

He has authored more than 80 journal articles and reports and is the senior author of his own book.