Five groups of rats representing as many different amounts of sexual indulgence were used. These amounts ranged from complete abstinence to excessive indulgence where opportunities for coitus were almost constantly present. The order of growth of the [female], as indicated by the average maximum body weight, in the 5 groups from the lowest to the highest was group A, virgins, 254 gm.; group E, excessive mating, hysterectomized rats, no breeding, 266 gm.; group B, light breeders (2 or 3 litters), 298 gm.; group D, heavy breeders (young destroyed at birth and mothers remated at first opportunity), 304 gm.; medium breeders (mothers reared as many Utters as possible), 306 gm. The similar order of growth of the [male] was: group E, excessive indulgence, 333 gm.; group B, light breeders, 338 gm.; group C, medium breeders, 340 gm.; group D, heavy breeding, 362 gm.; group A, strict bachelors, 363 gm. The [female] showed greater differences in weight than the [male]. All groups of [female] showed a tendency to increase weight after the menopause. An increase in weight of the [female] with sexual indulgence and a decrease in the amount of the follicular hormone were directly associated. Rats having sexual indulgence show a tendency to grow more rapidly in early life than abstainers. The bearing of young at an early age appears to inhibit body growth in later life.