“…Specific defects which have been investigated from this point of view include spina bifida (Hare, et al, 1966;Timson, 1970;Walker, Thomas, and Russell, 1971;Richards and McIntosh, 1973;Hunt, 1973), congenital heart disease (Polani and Campbell, 1955;Apley, Barbour, and Westmacott, 1967;Boon, 1972), and Down's disease (Newcombe, 1965). There are also a few references to reproductive behaviour following stillbirths and infant deaths (Newcombe and Rhynas, 1962;Sheps, 1965;Vogel and Knox, 1975) where no attempt was made to distinguish between malformations and other causes of death.…”