STAMFORD, Conn. — An Oxford couple on Wednesday sued a doctor who they say partially amputated their son’s penis during a circumcision at St. Vincent’s Hospital in Bridgeport.

Immediately after his injury last June, the day-old boy was transferred to Yale-New Haven Hospital where he underwent reconstructive surgery.

“We are bringing this case because we already know this baby has suffered a horrible, life-altering physical injury, but we are still learning about the long term ramifications of the injury,” said Ernest Teitell, one of the boy’s attorneys. “What happened will profoundly affect him as he grows older.”

Circumcision, often performed for religious reasons, involves removing foreskin from the penis. The American Academy of Pediatrics says most complications from the procedure, such as bleeding, are usually minor.

Robin Biondo, the boy’s mother, said Dr. Daniel S. Gottschall cut off 40 percent of the tip of her son’s penis.

“It was a very difficult thing to go through to see your new born child laying there and wondering how much pain he was in and how this is going to affect him,” Biondo said.

In 2001, a jury in California awarded $1.42 million to a 7-year-old boy for a botched circumcision. In another case, the late David Reimer, a Canadian, was born as a boy but raised as a girl after a botched circumcision.

The lawsuit, filed in Bridgeport Superior Court, seeks unspecified damages from Dr. Gottschall, who performed the surgery last June, and his medical and surgical group, Alliance for Women’s Health.

Gottschall said he has performed more than 1,000 circumcisions without a problem.

“There was a slight tip that was removed, recognized and repaired,” Gottschall said. “We believe there was a congenital deformity of the penis that made the injury more likely. Because of my diligence, the boy had the repair that was necessary.”

The boy, now nine months old, spent about 10 days in the hospital, according to his mother.

“We were always told it was uncharted territory because they had never seen anything like this before,” Biondo said.

The boy’s attorneys said the lawsuit was brought in part “because the family wants to make sure something this awful doesn’t happen to another child when their parents decide to have them undergo this same procedure.”