A gene that governs ovulation �?the release of a mature egg from a female's ovary �?has been identified by researchers in Canada and France, Canada's Globe and Mail newspaper reported Friday.

The finding means that a drug affecting the gene could be developed to treat infertility caused by a female's inability to ovulate. Conversely, a genetically based contraceptive could stimulate the gene to prevent ovulation, the newspaper said.

Researchers at the University of Montreal and at the Université Louis Pasteur deleted the gene, called Lrh1, from mice. This stopped ovulation, affected hormone cycles, seemed to prevent eggs from maturing, and stopped them from leaving the ovaries, the Globe and Mail reported.

The next step, the scientists said, is to collect ovarian cells from fertility clinics to see if these cells contain a defective Lrh1 gene.

The research is published in the current issue of the journal Genes and Development.

There were more births in the United States last year than at any time in the nation's history, according to a National Center for Health Statistics report cited by the Associated Press.

Some 4,315,000 babies were born in 2007, agency demographer Stephanie Ventura said.

While that amounts to roughly 15,000 more births than during the peak baby-boom year of 1957, Ventura discounted the notion of a new baby boom. She noted that there were far fewer women of childbearing age 50 years ago.

"What this really reflects is that the population has grown so much in the United States, so you naturally expect more births," she said. "It's hard to call this a baby boom at this point."

The sponsors of a planned human trial for an AIDS vaccine canceled the project Thursday, saying they doubted the vaccine's effectiveness and noted that the trial could actually put volunteers at risk of acquiring HIV, The New York Times reported.

The trial, called PAVE (Partnership for AIDS Vaccine Evaluation), was to be conducted by a consortium of U.S. agencies and private organizations. It was to have begun enlisting 8,500 volunteers last October to evaluate a vaccine developed by the National Institute of Allergy and Infectious Diseases.

The trial was shelved, however, after a similar vaccine developed by Merck & Co. failed to prevent the infection and lower blood levels of HIV among people who had already acquired the AIDS-causing virus, the newspaper said.

Data from the Merck vaccine trial also suggested that the shot might have increased some users' risk of acquiring an HIV infection.

Attempts to create an effective HIV/AIDS vaccine have been in the making for more than 25 years, and developing one still appears years away, scientists told the Times.