I find that fillies and mares win more at under 1.1,00 metres and over 2,000 metres in open company races, i have seen a large amount of fillies fail when favourite or near favourite when up in the weights , around saddle cloth 1 to 6.in 1,200 metres or middle distance races. In top 2yo and 3yo open gender races, usually maidens around big carnival times, often very well bred fillies from sprintting sires with the saddle cloth numbers 14 to 20 do win , there are always exceptions to the rules for example, sunline won a lot of races around 1,600 . Often you see races over 2,000 metres where there is only one filly or mare in the race and it does win because I believe fillies or mare prefer the really short races or the very long races over 2,000 metres.