mother child
The deliberate act of a parent killing their child is more common in the United States than most people expect. In this illustration, a mother is seen breastfeeding her child, while she smokes a pipe, St Giles, London, 1850. Getty Images

Filicide is the conscious act of killing one's own son or daughter. Despite it being a shocking thing to do, it is quite prevalent in the United States. A study by the Forensic Science International looked at over 30 years worth of filicide cases (between 1976 and 2007) and discovered that the heinous crime took place about 500 times a year in the U.S.

According to the study, the risk of filicide does not go away even when the children grow up enough to move out on their own. More than 13 percent of the victims are adults, aged 18 to 40 years, the study stated. Around 72 percent were 6 years old or even younger, and one-third of the victims were babies under the age of one.

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In 2014, USA Today conducted an examination consisting of more than three decades of FBI homicide data, which showed an average of 450 children in the U.S. were killed every year by their parents. The examination also analyzed the database to figure out who among the parents committed the crime more often and how.

The examination report claimed "nearly half of all victims died from physical beatings or other injuries at a parent's hands. Fathers are more likely to kill. Men killed six out 10 children, most often beating or shooting them. Fathers were at fault in 75 percent of cases when children were shot to death by a parent and in 64 percent of cases when a child was beaten."

"Violence is a masculine pursuit," said Jack Levin, a Northeastern University criminologist, who was a part of the examination.

However, the study by the Forensic Science International claimed that mothers are also likely to kill their children. The study concluded over 40 percent of the killers involved in filicide were mothers as compared to fathers who made up to almost 57 percent.

"People are fascinated by this," said Sara West, a forensic psychiatrist at University Hospitals Case Medical Center in Cleveland. "It's an unfathomable concept," she added, according to USA Today.

The study's lead author, Dr. Timothy Mariano, explained several theories as to why parents end up killing their own children. He said parents who are mentally ill and the ones who have high testosterone levels can resort to such a crime.

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One of the pioneers in filicide research, forensic psychiatrist Phillip J. Resnick, came up with five major reasons that could lead to such a heinous crime, according to CNN. These are as follows:

Accidental killing: A lot of parents physically abuse their children which might result in an unintentional outcome leading to death of the child.

Unwanted child: If a child is unwanted and acts as a hindrance according to the parents, it is quite likely they would kill their offspring.

Spousal revenge: Spousal revenge is when one parent would kill the child in order to take revenge on the other.

Altruism: In this case, the parents might kill their children because they think it is in their children's best interest like in cases of terminal illness. The parents might also kill their children before dying by suicide themselves as they feel it is unfair to leave the child alone to face the world all by themselves.

Acute psychosis: The parent might kill the child based on ideas and reasons that are considered to be inconsistent with reality. For example: Some parents might believe their child has been possessed by the devil.