mul·ti·fac·to·ri·al 
(mŭl′tə-făk-tôrē-əl)
(mŭl′tə-făk-tôrē-əl)adj.
1. Involving, dependent on, or controlled by several factors.
2. Of, relating to, or caused by a pattern of familial inheritance resulting from multiple genetic or environmental factors or from a combination of both.
mul′ti·fac·tori·al·ly adv.