[Chromosomal analysis of baboons and their mothers, following application to mothers of potentially post-ovulation fertility-inhibiting steroids (author's transl)].

One single does of 0.4 mg of steroid compounds Levonorgestrel (13-ethyl-17alpha-ethinyl-17beta-hydroxy-gon-4-en-3-on) or STS 557 (17alpha-cyanomethyl-17beta-hydroxy-13beta-methylgona-4.9-dien-3-on) was administered to each of six baboon mothers, right after mating. No indication whatsoever to possible mutagenic action of the compounds applied under the given experimental conditions were recordable from the bone-marrow cells of the mothers nor from the lymphocytes of peripheral blood of their newborns. Chromosomal aberrations recorded from this species were within normal limits.