A method of determining an inclusive residual risk that a pregnancy is
affected by at least one phenotypic disorder included in a disorder set
is provided. The method includes calculating a prior risk for a disorder
set, calculating posterior risks for the individual disorders or groups
of disorders in the disorder set that can be screened for and/or
diagnosed prenatally, and calculating an inclusive residual risk for the
disorder set by combining the prior risks for disorders for which no
tests have been performed and the individual posterior risks.