1) Estrogen 2) Hormonal contraception 3) Oestrogen 4) Synthetic estrogen 
(from the article `chemosterilant`) The female hormone mestranol can cause sterility in rodents, and triethylenemelamine can prevent the division of reproductive cells in male birds.
<chemical> (17 alpha)-3-methoxy-19-norpregna-1,3,5(10)-trien-20-yn-17-ol. The 3-methyl ether of ethinyl estradiol. It must be demethylated before it becomes biologically active. It is used as the oestrogen component of many combination oral contraceptives. ... Pharmacological action: oestrogens, synthetic. ... Chemical name: 19-Norpregna-1,3,...
(mes´trә-nol) a synthetic estrogen used in combination with a progestational agent as an oral contraceptive.
[n] - a synthetic form of estrogen used in combination with a progestin in oral contraceptives
noun a synthetic form of estrogen used in combination with a progestin in oral contraceptives