Not quite, but close. Bimodal distribution means the tendency is towards one of two categories, but with spaces both between and at the extremes of variance. In other words, while the majority fall comfortably under the bell curve of biologically male or female, there is variance both within and between these two categories; people who exhibit a greater or lesser degree or number of biologically masculine/feminine traits, for instance. As biology is extremely complicated, as you would expect, the precise variance of characteristics between biological men and biological women are far too complex and numerous to simply be accounted for in a basic binary model.