The novel D-homosteroids of the formula ##STR1## wherein R.sup.1 represents a --CN, .dbd.NOH or .dbd.CH--NHOH group; R.sup.2 represents oxo or, where R.sup.1 represents a --CN group, R.sup.2 represents oxo or a --OAc group; or R.sup.1 and R.sup.2 together with carbon atoms 2 and 3 of the steroid skeleton represents a [2,3-d]-fused isoxazole ring, a [3,2-c]-fused pyrazole ring, a [3,2-c]-fused N-acylated pyrazole ring or a [2,3-c]-fused furazan ring; Ac represents an acyl group; R.sup.3 and R.sup.4 represent methyl and R.sup.5 and R.sup.6 together represent an additional bond between carbon atoms 5 and 6 of the steroid skeleton; or R.sup.4 and R.sup.5 together represent --O--, R.sup.3 represents hydrogen or methyl, and R.sup.6 represents hydrogen; R.sup.7 represents hydrogen, lower-alkyl or ethynyl; R.sup.8 represents hydroxy or acyloxy; or R.sup.7 and R.sup.8 together represent a spiroether group of the formula ##STR2## or a spirolactone group of the formula ##STR3## the dotted 16,17-bond is an optional additional carbon-carbon bond; and the dotted 2,3-bond is an additional carbon-carbon bond when R.sup.1 and R.sup.2 together with carbon atoms 2 and 3 form the isoxazole or pyrazole ring or when R.sup.2 represents a --OAc group,inhibit the synthesis of progesterone in organisms and can be used for fertility control. The novel D-homosteroids can be manufactured by molecular modifications of other D-homosteroids.