11 alpha-Hydroxytestosterone (1a), 11 beta-hydroxytestosterone (1b), 11 alpha-methoxytestosterone (1c), 11 beta-methoxytestosterone (1d), 11-ketotestosterone (1e), and delta 9(11)-testosterone (1f) were synthesized from hydrocortisone (4b) or 11-epi-hydrocortisone (4a). The six target compounds, together with 11 alpha-methoxyandrostenedione (2c), 11 beta-methoxyandrostenedione, (2d) and their lead compound, testosterone (1), were found to effectively inhibit the growth and differentiation of human decidual cells in culture. There is no observable binding of these compounds to estrogen receptor of rabbit uterus. The introduction of a polar group (e.g., hydroxyl and carbonyl) to C-11 of androstenes decreases both the relative binding affinities to progesterone receptor and the inhibitory effects on human decidual cell growth, while the methylation of 11-hydroxyl group minimizes these effects. The similar effects of a polar group at C-11 of testosterone (1) on the inhibitory effects on human decidual cell growth and the relative binding affinities to progesterone receptor of rabbit uterus may suggest that one of the mechanisms of human decidual cell growth inhibition by these compounds is the anti-progestational activity of these androgens.