Antigen
Antigens are "targeted" by antibodies. Each antibody is specifically produced by the immune system to match an antigen after cells in the immune system come into "contact" with it; this allows a precise identification or matching of the antigen and the initiation of a tailored response. The antibody is said to "match" the antigen in the sense that it can bind to it due to an adaptation in a region of the antibody; because of this, many different antibodies are produced, each able to bind a different antigen while sharing the same basic structure. In most cases, an adapted antibody can only react to and bind one specific antigen; in some instances, however, antibodies may cross-react and bind more than one antigen.
Antiandrogen
In women who are pregnant, antiandrogens can interfere with the androgen-mediated sexual differentiation of the genitalia and brain of male fetuses. This manifests primarily as ambiguous genitalia – that is, undervirilized or feminized genitalia, which, anatomically, are a cross between a penis and a vagina – and theoretically also as femininity. As such, antiandrogens are teratogens, and women who are pregnant should not be treated with an antiandrogen. Moreover, women who can or may become pregnant are strongly recommended to take an antiandrogen only in combination with proper contraception.