The BBC news website looks at the problem of teenage pregnancy in the US after the revelation that the 17-year-old daughter of Alaska Governor and new Republican vice-presidential candidate Sarah Palin is pregnant.
Bristol Palin, seen holding her brother, is expecting a baby in December
The US is said to have one of the worst annual rates of teenage pregnancies in the developed world.
According to a report by Population Action International, published at the end of last year, there were 44 births per 1,000 women aged 15-19 in the US for 2000-2005.
This compares with figures in the UK - itself said to be the country with the worst teenage pregnancy rate in Europe - of 27 births per 1,000 women aged 15-19.
Put differently, America is estimated to have some 750,000 teenage pregnancies a year.
According to America's leading health agency, the Centers for Disease Control and Prevention (CDC): "About one-third of girls in the United States get pregnant before age 20."
Despite the continuous declines, the US teenage pregnancy rate is still among the highest among industrialised nations
More than 80% of births in this group "were unintended, meaning they occurred sooner than desired or were not wanted at any time", the CDC said.
Separately, in a report on 2002 data, the CDC said: "Despite the continuous declines, the US teenage pregnancy rate is still among the highest among industrialised nations.
"The costs of teenage childbearing in the United States are substantial.
"The National Campaign to Prevent Teen Pregnancy recently estimated that $9.1bn in public funding was expended on teenage childbearing in 2004. These costs include public assistance, healthcare, child welfare and other expenses."
Voters in Minnesota give their reaction
There is a debate state-side as to the reason for this high pregnancy rate.
The US offers government funding for health education programmes that promote sexual abstinence until marriage, although US lawmakers were investigating earlier this year whether to cut the funding.
State governments receive federal money they must match to fund abstinence programmes.
Opponents of abstinence education say the approach ignores the fact that teenagers are sexually active and fails to give them accurate medical information or advice on safer sex.
Governor Palin herself has said she opposes funding sexual-education programmes in Alaska and has supported abstinence programmes in schools.
"The explicit sex-ed programmes will not find my support," she wrote in a 2006 questionnaire distributed among gubernatorial candidates, the Associated Press reports.
A social conservative who is opposed to abortion, she said in a statement her daughter Bristol would keep the child and was to get married.
And in 2005, presidential candidate John McCain, who picked Mrs Palin as his running mate, opposed a Senate Democratic proposal that would have spent tens of millions of dollars to pay for pregnancy prevention programmes other than abstinence-only education, including education on emergency contraception such as the morning-after pill, AP reports.
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