WASHINGTON — President Bush on yesterday voiced support for anti-abortion demonstrators attending this year’s “March for Life” rally marking the anniversary of the Supreme Court’s Roe v. Wade decision.

This year marks 35 years since the landmark ruling that a woman has a constitutional right to have an abortion.

“Thirty-five years ago today the United States Supreme Court declared and decided that under the law an unborn child is not considered a person, but we know many things about the unborn,” Mr. Bush said, who hosted about 200 of the demonstrators in the East Room for coffee and doughnuts. In remarks being broadcast to other demonstrators later in the day, Mr. Bush said that biology confirms that from the start, each unborn child is a separate individual with his or her own genetic code.

“Babies can now survive outside the mother’s womb at younger and younger ages,” he said. “And the fingers and toes and beating hearts that we can see on an unborn child’s ultrasound come with something that we cannot see: a soul.”

Despite chilly weather, tens of thousands of people were marching from the mall to the Supreme Court. The National Organization for Women was staging a counter protest.