"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.
"Gaza woman found slain in most recent 'honor killing," from the Ma'an News Agency, June 11 (thanks to Maxwell):
Gaza - Ma’an - The body of a 21-year-old woman was uncovered in the Gaza Strip on Wednesday in the Deir Al-Balah Refugee Camp in a murder that appeared to be an “honor killing.”...
In their investigation, PCHR said police sources “revealed that the victim's father issued a confession to the police” that he had killed his daughter to “preserve family honor.”
According to PCHR's documentation, the number of people killed allegedly "to maintain family honor" since the beginning of 2009 has reached 8 (5 women, two men and a child) in 6 separate crimes. Seven of the crimes were committed in the Gaza Strip.