Some preferred estrogenic nuclei include but are not limited to: ##STR20## wherein x is a halogen, preferably chlorine or iodine; wherein R3 and R4 are independently selected from the group consisting of hydrogen, lower alkyl, lower alkoxy carbonyl, (C1 -C20), alkanoyl, (C3 -C20) alkenoyl, (C3 -C20) alkynoyl and (C7 -C11) aroyl, alkylsilyl, 1-alkyloxy-alkyl and 1-alkyloxy cycloalkyl; or ##STR21##