The Gender Genie analyzes text and determines gender based on the occurrence of certain words, the parts of speech to which these words belong, the use of contractions and punctuation, and other such metrics.

Recently /r/MensRights has seen an influx of troll self-posts where a female impersonates a male OP for whatever reason. Using this tool, we can better determine the gender of the OP and thus better determine the likelihood that the OP is a troll if, for example, they insist on being a man in a terrible situation, but consistently write like a woman.

The algorithm isn't perfect, and there are bound to be false-positives, so avoid using this to trump people in an argument or attempt to say that the results are absolutely irrefutable. For example, some of my past comments register as female, and running some of GirlWritesWhat's comments register as male. That said, the results are more accurate when combining several of the user's comments from different days/weeks - as opposed to testing a single comment.

I've recreated the algorithm using Python's NLTK, Natural Language Toolkit, and have had been able to reproduce Gender Genie's results, so I highly doubt their tool is nothing more than guesswork based on simple word counts. I'll share the implementation with those non-trolls who are also programmers and/or interested in the code.