The guidelines stop short of telling parents to get their sons circumcised. That is a personal decision that may involve religious or cultural preferences, said Dr. Jonathan Mermin of the US Centers for Disease Control and Prevention, or CDC.
But "the scientific evidence is clear that the benefits outweigh the risks," added Mermin, who oversees the agency's programs on HIV and other sexually transmitted diseases.
Germs can grow underneath the foreskin, and CDC officials say the procedure can lower a male's risk of sexually transmitted diseases, penile cancer and even urinary tract infections.
The CDC started working on the guidelines about seven years ago, when a cluster of influential studies in Africa indicated circumcision might help stop spread of the AIDS virus.
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"The benefits of male circumcision have become more and more clear over the last 10 years," said Dr. Aaron Tobian, a Johns Hopkins University researcher involved in one of the African studies.
It gradually became the cultural norm, and in the 1950s and 1960s surpassed 80 percent. But then the trend reversed. Part of it had to do with changing demographics, as the U.S. population grew to include larger numbers of Mexican-Americans and other ethnic groups that didn't traditionally circumcise their children.
Also, opposition to the procedure was aided by the Internet and by the neutral stance of physicians groups.
By 2010 the newborn circumcision rate was down to about 58 percent, according to one CDC estimate.