A British woman pregnant at age 63 defended her right to be an older parent Thursday, saying her decision to have another child was not undertaken lightly.

Patricia Rashbrook, a child psychiatrist from Lewes, south of London, has two grown children from a previous marriage but recently remarried and underwent fertility treatment. She is due to give birth in two months.

"We take our responsibilities very seriously and regard the best interest of the child as paramount," Rashbrook said. "And what we would wish now is to be allowed the right to pursue our family life in private."

The couple did not say what fertility treatment Rashbrook received. News reports said she may have been treated by Italian Dr. Severino Antinori, who in 1994 helped a 63-year-old woman become pregnant using hormone treatment and donor eggs.

Most of the criticism of Rashbrook's decision to have a child has come from conservative groups that oppose abortion and some types of assisted fertility treatment.

"It is extremely difficult for a child to have a mother who is as old as a grandmother would be," said Josephine Quintavalle, co-founder of Comment on Reproductive Ethics. "It is just that consumer society that wants absolutely everything, and never stops to think that a child is not a product."

James Healy of Britain's Human Fertilization and Embryology Authority, which regulates fertility treatment, said the law sets no age limit for treatment, which is "left to the clinical judgment of doctors."

"But the law says that clinics must take into account the welfare of the child, including the health, age and ability to provide for the needs of the child or children," he said.

In a statement, Rashbrook and her husband, John Farrant, said the pregnancy "has not been an endeavor undertaken lightly or without courage."

"A great deal of thought has been given to planning and providing for the child's present and future well-being, medically, socially and materially," the couple said.

"We are very happy to have given life to an already much-loved baby, and our wish now is to give him the peace and security he needs."

Other older British mothers include Liz Buttle, from Wales, who was 60 when she gave birth to a son in 1997.

The oldest woman in the world to give birth is believed to be Romanian Adriana Iliescu, who was 66 when she had a daughter in Bucharest in January 2005.