It's Not Illegal for Parents to Kill Their Own Children

Robert Spencer, in an article entitled Trashing a Freedom Fighter, wrote:

A manual of Islamic law certified as a reliable guide to Sunni orthodoxy by Al-Azhar University, the most respected authority in Sunni Islam, says that “retaliation is obligatory against anyone who kills a human being purely intentionally and without right.” However, “not subject to retaliation” is “a father or mother (or their fathers or mothers) for killing their offspring, or offspring’s offspring.” (‘Umdat al-Salik o1.1-2).

In other words, someone who kills his child incurs no legal penalty under Islamic law.