I want to see some references, because I think you're making stuff up.

According to the Bureau of Justice Statistics...

In 2004 (I could get more recent stats, but these were the top of the Google and I'm lazy and I doubt there's a whole lot of difference), males were 10 times more likely than females to commit murder.

Additionally, only a third of the females incarcerated in the US are in for a violent crime compared to half of the males incarcerated being in for a violent offense.

I see nothing anywhere that suggests that women attempt murder as often as males. They do use poison and other indirect means more often than men, but you have no way of quanitfying that in a way that is suggestive of identical attempt rates.

I'm willing to accept that I'm wrong if you show me where you got your information. But working in a prison with women, only two of which are in for murder, leads me to believe that you're incorrect.