Genistein was, among other flavonoids , found to be a strong topoisomerase inhibitor , similarly to some chemotherapeutic anticancer drugs ex. etoposide and doxorubicin .   In high doses it was found to be strongly toxic to normal cells.  This effect may be responsible for both anticarcinogenic and carcinogenic potential of the substance.   It was found to deteriorate DNA of cultured blood stem cells, which may lead to leukemia.  Genistein among other flavonoids is suspected to increase risk of infant leukemia when consumed during pregnancy.