<FORM:0929271/IV(a)/1> The invention comprises 10a -methyl-9b steroids of the general formula A shown in the Figure, wherein R1 represents a hydrogen atom or a methyl group, R2 represents no double bonds or one or more double bonds at one or more of the positions 1, 2, 3, 4, 5, 6, 15 and 16, R3 represents a hydrogen atom or a methyl, ethyl, hydroxy, etherified hydroxy or esterified hydroxy group, R4 represents a keto, hydroxy, etherified hydroxy or esterified hydroxy, R5 represents a hydrogen or halogen atom, R6 represents a hydrogen or halogen atom, or a methyl, hydroxy, etherified hydroxy or esterified hydroxy group, R7 represents a hydrogen or halogen atom, R8 represents hydrogen or a hydroxy or keto group, R9 represents a hydrogen atom or a saturated or unsaturated hydrocarbon group having from 1 to 6 carbon atoms or such group in which one or more hydrogen atoms is or are replaced by hydroxy, etherified hydroxy or esterified hydroxy and/or double bonds, R10 represents a hydrogen atom or a hydroxy, etherified hydroxy or esterified hydroxy group (R9 and R10 are not both hydrogen), or R9 and R10 represent a keto group, and R11 represents a hydrogen atom or a hydroxy, etherified hydroxy or esterified hydroxy group the preparation thereof in the case where R9 and R10 together represent a keto group by oxidising a compound of the general formula J in the Figure wherein X has the formula shown in the Figure (R1 to R8 and R11 having the above significance), QVI represents a methyl group and QVII represents an aldehyde group or a cyanhydrin or bisulphite addition product derived therefrom or an O-acyl group, or QVI represents hydrogen and QVII represents a -COOR group in which R represents an aliphatic hydrocarbon group containing from 1 to 6 carbon atoms the preparation thereof in the case where R9 represents hydrogen and R10 represents a hydroxy, etherified hydroxy or esterified hydroxy group by reducing the corresponding compounds wherein R9 and R10 together represent a keto group to form a 17-hydroxy group, for example, by means of a complex metal hydride or catalytic hydrogenation (this step may cause reduction of a 3-keto group to a 3-hydroxy group and selective oxidation may be used to reform the 3-keto group, for example, by the action of manganese dioxide or the 3-keto group may be protected by conversion into a 3-enamine or 3-glycol acetal) and, when required, esterifying or etherifying the 17-hydroxy group the preparation thereof in the case where R9 represents a saturated or unsaturated hydrocarbon group containing from 1 to 6 carbon atoms and R10 represents a hydroxy, etherified hydroxy or esterified hydroxy group, by reacting the corresponding compound wherein R9 and R10 together represent a keto group with a metal acetylide, a Grignard reagent or equivalent organometallic compound capable of reacting with a keto group and, when required, etherifying or esterifying the 17-hydroxy group the preparation thereof in the case wherein R9 represents a hydroxyacetyl, or an ehterified or esterified hydroxyacetyl group and R10 represents a hydrogen atom, a hydroxy group or an etherified or esterified hydroxy group, by acylating a 10a -methyl-10b -steroid of the general formula Z2 in the Figure wherein R1 to R8, R10 and R11\t have the above significance and Hlg represents a halogen atom with an alkali metal or alkaline earth metal salt of an organic carboxylic acid and, when required, saponifying to form a 21-hydroxy compound and etherifying the 21-hydroxy compound the preparation thereof in the case wherein R9 represents an acetyl group and R10 represents hydrogen by oxidising a 10a -methyl-9b -steroid of the general formula D in the Figure in which X has the above significance, QIV represents a secondary amine residue, an O-acyl group, a C1 to C6 alkyl group or a phenyl group, and QV represents a hydrogen atom, or QIV and QV each represent a C1 to C6 alkyl group or a phenyl group, with an oxidising agent capable of breaking the 20(22) double bond such as ozone, chromium trioxide, sodium, potassium or ammonium dichromate or potassium permanganate (with ozone an intermediate ozonide is formed which must be decomposed with a reducing or oxidising agent) the preparation thereof in which R9 represents an acetyl group and R10 represents a hydroxy group by treating a 10a -methyl-9b -steroid of the general formula J shown in the Figure, wherein QVI represents a methyl group and QVII represents an aldehyde group and X has the above significance, and hydrolysing the resulting epoxy-10a -methyl-9b -steroid of the general formula M in the Figure wherein X has the above significance the preparation of 10a -methyl-9b -steroids of the general formula S2 shown in the Figure, wherein R2 represents, besides the D 1-double bond, no double bonds or one or more double bonds at one or more of positions 4, 5, 6, 15 and 16, and R1, R3 and R5, R11 have the above significance, by dehydrogenating the 10a -methyl-9b -steroids of the general formula S8, shown in the Figure, wherein R2 represents no double bonds or more or more double bonds at one or more of the positions 4, 5, 6, 15 and 16, by halogenation followed by dehydrohalogenation, by biochemical dehydrogenation, or by treatment with selenium dioxide, selenic acid, iodine pentoxide or iodic acid with substances generating the same during the reaction the preparation of 10a -methyl-9b -steroids of the general formula T3 shown in the Figure wherein R1, R2 and R3 and R5 to R11 have the significance indicated above for formula A and Alk represents a methyl or ethyl group, by treating the corresponding 2-unsubstituted compound of the general formula T1 shown in the Figure with a dialkyl ester of oxalic acid in the presence of an alkali metal hydride or alkoxide or equivalent condensation reagent to form a condensation product and converting the condensation product to a 10a -methyl-9b -steroid of the general formula T2 shown in the Figure wherein R12 represents the alkyl group of the alkyl oxalate, for example, by means of acids, and treating this 9b -compound with a methyl or ethyl halide the preparation of a 10a -methyl-9b -steroid compound of the general formula Y2 shown in the Figure by selectively D 6-dehydrogenating a 10a -methyl-9b -steroid of the general formula Y1, wherein R1, R3 and R5 to R11 have the significance indicated above for formula A and R2 represents no double bonds or one or more double bonds at one or more of the positions 1, 2, 15 and 16, with chloranil or by suitable halogenation at the allylic position in relation to the D 4-double bond followed by dehydrohalogenation a method for the preparation of a 10a -methyl-9b -steroid of the general formula Z3 shown in the Figure by treating a 10a -methyl-9b -steroid of the general formula Z1 shown in the Figure, wherein R1 to R8, R10 and R11 have the significance indicated above for formula A and R12 represents a hydroxy, etherified hydroxy or esterified hydroxy group, with lead tetracetate or 21-hydroxylating microorganisms to introduce the 21-hydroxy group and, when required, etherifying or esterifying the 21-hydroxy group 21-hydroxy group may also be introduced by halogenating the 10a -methyl-9b -steroid of general formula Z1a shown in the Figure (obtainable from the 10a -methyl-9b -steroid of formula Z1 by condensation with a dialkyl oxalate in the presence of an alkali metal alkoxide so that m represents an alkali metal and R is an alkyl group derived from the dialkyl oxalate), reacting the resulting 21-halo compound of formula Z2 with a metal acylate and hydrolysing the resulting 21-acyloxy compound to a 21-hydroxy compound and, when required, esterifying or etherifying the 21-hydroxy compound. The above processes may be modified in that the reactants may be prepared by processes described in Specifications 929,276, 929,277, 929,278 and 929,279. At any stage in the above processes it is possible to introduce a D 1-double bond by dehydrogenation with iodine pentoxide, iodic acid, selenic acid or selenium dioxide, or by biochemical dehydrogenation, or by dehydrohalogenation to introduce at the 2-position an alkyl, halo, ester, hydroxy or ether substituent by reaction of a 3-ketone with an oxalic ester followed either by alkylation with an alkyl halide to form a 2-alkyl substituent or halogenation to form a 2-halo substituent which may be converted to a 2-ester p group, then hydrolysed to a 2-hydroxy group, and finally etherified to a 2-ether group to introduce a D 6-double bond by allylic halogenation of a D 4-compound followed by dehydrohalogenation to oxidise a 3-hydroxy group to a 3-keto group or to esterify a hydroxy group such as a 3- or 17-hydroxy group. The Specification refers to a large number of 10a -9b -steroids of the general formula A shown in the Figure. Therapeutic compositions contain as the active ingredient a 10a -methyl-9b -steroid of the general formula A shown in the Figure, wherein R1 to R11 have the above significance, and a solid or liquid excipient. The composition may be in a form suitable for administration orally or by injection, and may have androgenic, anti-androgenic, oestrogenic, anti-oestrogenic, progestational, anabolic, anti-ovulatory or anti-inflammatory activity. Specification 929,272 also is referred to.