The availability of abortions on demand, as provided by the new New York State abortion law, had a profound effect on fertility in a large community with previously very restricted access to illegal abortions. Improved family planning and the availability of abbortions as a backup measure combines with a preference for a smaller family size led to a one-third reduction of live births in the short period since the new law became effective. Planning for paediatric and obstetric care had to be adjusted accordingly. The frequently hypothesized or reported secondary effects on illegitimacy or infant mortality could not be observed. The trend towards increasing illegitimacy was slowed down, but not reversed. Infant mortality continued its short-term erratic pattern; the trend towards a higher proportion of teenage pregnancies cancelled the effect that pregnancies at higher risk for infant death are also at higher risk for abortion.