An individual that considers gender to be private information , and that uses different genders in different situations is very unlikely to be using a name that can be classified with a high degree of confidence as one gender.

A person using the name "Jack" is unlikely to be assumed to be a woman, even if that person selected "female" from a drop down somewhere. If the same person uses Jack/M and Cindy/F in different contexts, no fuzzy algorithm is going to resolve them as the same person (bar some other, stronger ID, such as a SSN).

EDIT: I initially used "William" as an example. Ironically, it turns out that name is only 57.6% male. Both Jack and Cindy are 90% male/female.