A REEXAMINATION OF THE SEX-RATIOS OF FAMILIES WITH A NEURODEVELOPMENTALLY DISORDERED CHILD

It has been claimed that mothers with certain hormonal imbalances and/ or immunological disorders are more likely to give birth to male than female children and that they are more likely to give birth to a neuro developmentally disordered (ND) child. Liederman and Flannery (1995) r eported that the sex ratio of families with an index ND child did not significantly differ from the sex ratio of families without an index N D child. The data were derived from the National Collaborative Perinat al Project (NCPP). James (in the current issue) challenged us to recon sider the standard against which we judged the sex ratio of siblings o f ND children, since the 1.10 sex ratio that we obtained for the sibli ngs of non-ND children is much higher than the sex ratio of children b orn during that period according to the U.S. Census Bureau. In the cur rent paper, the NCPP data were reexamined and it was demonstrated that the high sex ratio of siblings in our non-ND sample was not due to va rious retention or recruitment biases. Thus, we suggest that use of th e sex ratio of siblings of non-ND children was the proper standard aga inst which to judge the sex ratio of ND families, and that our data pr ovide no evidence to support the notion that these families are male b iased. Copyright (C) 1996 Association for Child Psychology and Psychia try.