What an interesting thread!
First, I really am a male, and DW is another Gransnetter in her own right. I suspect DDs may dip into Mumsnet. I really cannot remember how or when I was introduced to Gransnet, but it was some years ago, and I have always found the range of topics interesting, from politics to grandparenting to AIBU to the more frivolous threads. The ones about sex and gender I have found particularly informative, as it is not a topic to which I had previously given much thought.
I feel no need for a male equivalent, even when some Gransnetters are up in arms about the patriarchy. I just duck!