From 'Freakonomics' : When a Woman Doesn't Want a Child

When a woman does not want to have a child, she usually has good reason. She may be unmarried or in a bad marriage. She may consider herself too poor to raise a child. She may think her life is too unstable or unhappy, or she may think that her drinking or drug use will damage the baby’s health. She may believe that she is too young or hasn’t yet received enough education. She may want a child badly but in a few years, not now. For any of a hundred reasons, she may feel that she cannot provide a home environment that is conducive to raising a healthy and productive child.

UNWANTEDNESS Leads to HIGH CRIME.