 Mycoestrogens, estrogenic substances from fungi, are another type of xenoestrogen that are also considered mycotoxins.Xenoestrogens are clinically significant because they can mimic the effects of endogenous estrogen and thus have been implicated in precocious puberty and other disorders of the reproductive system.Xenoestrogens include pharmacological estrogens (estrogenic action is an intended effect, as in the drug ethinylestradiol used in contraceptive pill), but other chemicals may also have estrogenic effects.