But Justice Sandra Day O'Connor, who was the tie-breaking vote, retired late last month and was replaced by Samuel Alito. Abortion had been a major focus in the fight over Alito's nomination because justices serve for life and he will surely help shape the court on abortion and other issues for the next generation.

Alito, in his rulings on the 3rd U.S. Circuit Court of Appeals in Philadelphia, has been more willing than O'Connor, the first woman justice, to allow restrictions on abortions, which were legalized in the Roe v. Wade decision in 1973.

The federal Partial-Birth Abortion Ban Act prohibits a certain type of abortion, generally carried out in the second or third trimester, in which a fetus is partially removed from the womb, and the skull is punctured or crushed.

Justices on a 9-0 vote vote reaffirmed in January that states can require parental involvement in abortion decisions and that state restrictions must have an exception to protect the mother's health.

The federal law in the current case has no health exception, but defenders maintain that the procedure is never medically necessary to protect a woman's health.

ONS editor Hayley Butcher said: "Although most children are born to married couples, this substantial rise in births outside marriage is a reflection of the rising trend in cohabiting parents."

From 1986 to 2004, the percentage of non-married people under 60 who cohabited rose from 11% to 24% among men, and from 13% to 25% for women.

Living alone

The number of households in the UK increased by 30% - from 18.6 to 24.2 million - between 1971 and 2005.

The average household size fell from 2.9 to 2.4 people over the same period.

Some seven million people lived alone in 2005 - representing 29% of all households, up from 18% in 1971 - the ONS said.

The ONS said that in the 1980s and 1990s one-person households mainly comprised older women, who tended to live longer than men.

But recent years had seen an increasing tendency for people to live alone at younger ages.

The largest increases in the last 20 years had been among people aged 25 to 44, and men from 45 to 64.

The ONS' Social Trends study also reported that young men were more likely to live with their parents than young women.

Some 57% of men aged 20 to 24 lived with their parents in 2005 - up from 50% in 1991 - compared with just 38% of women - up from 32%.

"Some young people may remain at home while in education or because of economic necessity, such as difficulties entering the housing market," the report said.

The Social Trends study's other findings included:

* In spring 2005, one in five full-time employees reported usually working more than 48 hours a week.

* Passengers travelling to or from overseas countries through UK airports (excluding transit passengers) almost quadrupled between 1980 and 2004, from 43 to 167 million.

* More than one billion journeys were made on the national rail network each year in 2003-4 and 2004-5 - the highest level since 1961.

* Transactions using debit cards increased ten-fold from 1991 to 2004, while credit card transactions trebled.

* The number of UK households that owned second homes abroad rose 45%, to almost 257,000, from 1999-2000 to 2003-4.

"She felt she was basically commanded, in essence, to cut Maggie's arms off and her own arms off, and her legs and her head, and in some way to give them to God," said Self, who evaluated Schlosser in the months after her arrest.

Police found Schlosser in her living room, covered in blood, still holding a knife and listening to a hymn. She had sliced deep into her own shoulder and chopped off her baby's arms. Schlosser, 37, has pleaded not guilty by reason of insanity, and her attorneys are trying to prove she did not know right from wrong when Margaret, also known as Maggie, was killed.

Prosecutors, who are not seeking the death penalty, argue Schlosser knew what she was doing and should be sent to prison for life. If found not guilty, Schlosser would be hospitalized.