I will not attack this subject with feministic aggression (though some of the responses nearly provoke me to do so, given their failure to grasp the subject) but say that, in my opinion, an understanding and love of Bach is not dictated by gender but by development and social circumstances. This cannot be addressed briefly or be made specific only to Bach; it is a matter of total development.
I am 15, female and adore Bach with every fibre of my being. This has not always been so; though I have never had a specific "favourite" composer, I did abhor some composers in my younger life. Mozart was at the top of this list, his melodies making me feel patronised and frustrated at four years old. After that was Bach, admittedly; it was "square" music, as I expressed it, being too abstract an expression of musical ideals for a mere child to grasp.
In very early childhood, I could hardly listen to a Chopin Polonaise, finding it "too bombastic". Satie was my favourite composer, and almost everything else nearly physically hurt my ears. I lost this particular sensitivity when I attended school, for external influences to which I had not been previously exposed (such as other children screaming in my face) quickly desensitised me to loud sounds. At this time, I began piano lessons, and one of my immediately favoured composers was Beethoven, for his music appealed to my childish (not feminine) enjoyment of brilliant dynamics and well-structured changeable music; I did not understand that in such an analytical sense at the time, but rather like a child staring at a beautiful face, not realising that it is the fulfilment of perfect, complex mathematical equations but finding it simply beautiful and appealing. I was not yet able to enjoy Bach in that subconscious way, his music provoking in me the feeling which comparatively “bombastic” music had when I was a toddler, shocking me with the metronomic, abrupt way in which it forced itself upon my ears.
At nine, I moved into the Romantics and Neo-Romantics, Chopin and Rachmaninoff particularly, though beginning to enjoy a good Bach/Busoni transcription, though for the passion and not the form.
After leaving school at thirteen (am currently doing distance education to satisfy BOS), I dedicated my life completely to music, reading composer letters and biographies, trying to understand the complexities of composition and generally becoming a "complete musician"; one cannot play with full command if one does not understand every aspect of the music and the context from whence it came. This revealed to me quite how wonderful Brahms was, being a close love of mine to this day (and, I think, all to come).
I began to understand the perfection of Bach at fourteen, not playing but hearing it. Ran Dank played the Prelude and Fugue in E-flat minor (bk.1, WTK) in SIPCA, and upon hearing the first, tender notes of the Prelude, I began to cry irrepressibly. At that point, I was more emotionally touched by that minor third than I was by all of the chords crammed into the cadenza of the Rach three. The performer, I admit, had beautiful tone which gave the piece more impact than it may otherwise have had, but the essential beauty of the composition was simply enhanced and not created by that. As I heard the fugue unfold, I understood that Bach was incredibly complex, expressive and tender, and not hard and detached as I had formerly found his work.
From that point, I became obsessed by fugues, and have analysed my current fugue four times in four different ways; separating voices, colouring each section according to the emotion therein, deciding which themes and/or motives on which I should focus and finally writing the ways in which each subject, counter subject and recurrent episode should be played in order to achieve a perfectly consistent, understood and mastered fugue. Each time, I find a new “layer” at which I may marvel.
I would come to the conclusion that it is external influences which determine the understanding of music, Bach in particular. External influences in most societies are possibly less conducive to a female understanding of Bach, and as such may be understood as a primarily masculine joy. I am probably the last person who may give a direct report of female appreciation of any music, let alone Bach in particular, having never associated with anyone who likes classical music, given my relatively isolated and short life. However, consider me a “control” experiment if you will; a female unshaped by popular culture and immersed solely in classical music, who has independently come to the conclusion that Bach is perfect, expressive and wonderful.
Summary; nurture, not nature (understanding -due to influence-, not gender).