While it is true that serial killers are statistically more likely to be men, women are perfectly capable of racking up an impressive body count, though the killing methods of the two sexes tend to differ. Typically male serial murderers gravitate towards performing violent and bloody atrocities against the (usually female) body; women, in contrast, have historically turned to the comparatively gentle, more hands-off method of poisoning.
Victorian England, in fact, saw the rise of the woman poisoner as a cultural archetype. After all, poisons such as arsenic were easy to come by and forensic science was not yet adept at detecting such causes of death. To be fair, married women had little or no rights then, and poison often presented the only means out of an abusive marriage. I admit I have a something of a soft spot for women who poisoned out of self-preservation.
