Teenage pregnancy is a uniquely modern problem, right-wing commentators say. It is the scourge of an immoral generation and unequivocal proof of declining standards.
And to some extent they are right. New research reveals that while schoolgirls have always fallen pregnant, the concept of teenage motherhood did not exist until 1961.
During the 1950s, extramarital sex was still widely condemned. In her report, Ofra Koffman, a research fellow at Goldsmiths, University of London, points out that unmarried women who became pregnant often lost their jobs and homes, and some were ostracised by their families.
Every year from 1957 to 1961, London County Council placed approximately 1,000 women into designated mother-and-baby homes.
Teenage mothers were not regarded as distinct from older single mothers. Instead, women were divided according to whether it was their first or second pregnancy; those failing to "learn their lesson" were seen as corrupting.
But in the late 1950s, government officials argued that teenage mothers should be housed separately, to keep them away from repeat offenders and to enable the Government to provide them with schooling and longer-term support.
St Christopher's home for pregnant schoolgirls opened in south London in April 1961. Its residents came from all over England; most were aged 14.
This is when the notion of teenage mothers as children in adult bodies began to emerge. A council report stated: "Many of the girls are so young that they really require mothering, and their separation from their parents frequently results in a need for psychiatric help."
St Christopher's engaged a psychiatrist, Donald Gough, to visit each girl just after she had given birth. He claimed that psychological help given then could profoundly influence the future development of mother and baby.
In 1966, Dr Gough said teenage motherhood was unfortunate because "it is often very doubtful whether these two sets of children can be assured the provision for normal emotional development".
The more work that psychologists undertook with St Christopher's inmates, the more problematic teenage pregnancy appeared. A 1965 Moral Welfare Workers' Association bulletin asked: "Can a girl so young face this dichotomy of personality: at school a child, at home a mother?"
"It reinforced the depiction of the pregnant schoolgirl as someone who is not fully grown up," Dr Koffman said. "Although physiologically she is shortly to become a mother herself, psychologically, she is still in need of mothering."
The conclusions of these 1960s psychiatrists still determine how teenage mothers are perceived and treated today.
Both Gordon Brown and David Cameron have spoken about the problems of "children having children". It has become an accepted truism that a sexually mature body does not necessarily reflect a mature mind.
Dr Koffman argues that this assumption should not be accepted blindly. "The notion of a discrepancy between the body and the psyche is so widespread that it is often implicit," she said.
"However, it is precisely this idea that we need to question, as it is by no means universal ... In some societies, sexual maturation is a prime indication that a person is prepared for the transition into adulthood."