measured liability irrespective of parental phenotype, and is hence much more feasible, yields increases in power similar to the high-risk designs with the previously mentioned exception of extreme environmental risk sampling. We contend that the low-risk design is substantially more feasible and similar to sampling approaches that have been used with success in complex disease genetics for more than a decade (N. Risch & Zhang, 1995; N. J. Risch & Zhang, 1996).
