Ingram Olkin has an excellent editorial about gender equality in statistics departments in the US.  Everyone should read it. 

Each University has its own business structure, and UCLA has its own structure. Biostatistics also differs from statistics in a lot of important respects, particularly with regard to soft and hard money. I looked at UCLA Biostat based on information from our web site.  Counting everyone listed as Professor in our directory, we had 2 Female out of 17 Full Professors, 4/4 Associate Professors, and 3/5 Assistant Professors. These numbers include joint and secondary appointments, and part time and non-tenured professors. Doing my best to count faculty with tenure in Biostat, I get 1/8 Full, 2/2 Associate and 0/1 Assistant Professors. It may sound funny to hedge ("Doing my best"), but I really didn't know how many people we had until I counted just now. For the tenured count, I again took my best guess. (Mistakes may get made!) One full male prof is actually split between two departments, so saying we have 1 female out of 7.5 tenured full professors might be slightly more accurate. 

UCLA Biostat may not be doing too bad at the junior ranks in terms of gender diversification. Numbers are obviously not the whole story; atmosphere, support, opportunities also matter immensely. Senior faculty ranks are clearly lopsidedly male.

We all have to continue to actively support gender equality in hiring and promotion. Semper Vigilo