You can't exclude women of a serious study based on these silly assumptions that the results might be different. Results in women would provide the kind of nuance in the conclusions that would strengthen this paper. Because this type of study only offers correlations between properties and does not establish causation, you need all the nuances you can get. This is not even a biological study, because it not linking testosterone to other biological functions. It is linking biology to intangible constructs such as generosity so I am not sure what the excuse is. I would argue that if testosterone has this effect on generosity, the effect would be more pronounced in women because this group tends to have lower levels of this hormone in general so any increase in level relative to the average would yield marked differences in generosity. Unfortunately the study does not provide the necessary data to evaluate this hypothesis. Merry Christmas!