The Collaborative International Dictionary of English v.0.48:

dysgenics \dysgenics\ n.
   the study of the operation of factors causing degeneration in
   the type of offspring produced.

   Syn: cacogenics.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

dysgenics
    n 1: the study of the operation of factors causing degeneration
         in the type of offspring produced [syn: dysgenics,
         cacogenics] [ant: eugenics]