filicide

from WordNet (r) 3.0 (2006)

filicide
    n 1: a parent who murders his own son or daughter
    2: the murder of your own son or daughter

from The Collaborative International Dictionary of English v.0.48

Filicide \Fil"i*cide\, n. [L. filius son, filia daughter +
   caedere to kill.]
   The act of murdering a son or a daughter; also, parent who
   commits such a murder.
   [1913 Webster]