Male axillary secretions influence women's menstrual cycles: a critique.

W. B. Cutler et al. report in the December 1986 issue of Hormones and Behavior (20, 463-473), that women treated with axillary extract from male donors showed reduced variability in menstrual cycle lengths and a reduced proportion of aberrant cycles. The initial samples--seven subjects treated with the male extract and nine subjects treated with blank/ethanol--did not differ significantly in the frequency of aberrant and normal cycles. The cycles of four subjects who were having weekly coital activity were removed from the samples, since coital activity has been shown to be associated with normal-length cycles. The frequency differences of aberrant and normal cycles in the reduced extract and placebo samples were statistically significant. The experiment's conclusions are questionable because (1) the decision to remove the cycles of the four women who had weekly coital activity was not justified by the evidence from this experiment and (2) the researchers lacked an observed preexperimental data base from which to measure changes in the women's cycle lengths.