Sick SIck and Hormone are different. They shouldn't be same, one is about giving someone sickeness and other is control and generation of different homones(Ivankov creates the hormones pretty much creating drugs so hers is more of creating medicine(not really) you can say while sick sick should ideally be infecting someone with disease), but oda gave it the gender ability of hormone..god knows why. Just for random plot as usual I guess...I mean the reveals now pretty much say that he just is giving them stuff to make them stronger and "interesting".