You have to remember that many concentration camps served both the purpose of extermination and slave labour. At the selection procedure at the start, the weak, children, pregnant, mothers with children, and elderly were doomed to a direct death in the gas chambers. By default then, women were more likely to die from the outset in the gas chambers, while the men were more likely to die from malnutrition and disease in the camps. Of course many men still died in the gas chambers and many women died in slave labour camps, but this initial discrepancy will at the very least have already turned the odds in favour of a larger cache of male writings about the holocaust.

Apart from that, I do not know what the survival rates of the camps are when comparing men to women, perhaps someone else could chime in?

I don't know why the majority appear to be authored by men, but I can recommend the following:

• The Hiding Place, by Corrie ten Boom
• The Woman Without a Number, by Iby Knill
• This Holocaust Learning site for short testimonies about survival, the majority of which are female-authored

There is Ravensbruck: Life and Death in Hitler's Concentration Camp for Women It was published as 'If This Is A Woman: Inside Ravensbruck: Hitler's Concentration Camp for Women' in the UK. There is a review of it in The Guardian

I suggest looking into the writings of Hannah Arendt. She is arguably the most influential writer on the relationship between totalitarianism and terror.