- You should look to connect with partners at firms that have female founders (ideally purely female-founding teams) among their portfolio. There are also a few female partners out there as well -- get access to them, with your YC network it should not be hard. Listen hard and press them to get honest, specific feedback when given "no"s.
- While the sexism is unfortunate and it's hard not to get frustrated, you may want to look long and hard at your pitch and company. If you've really talked to 40 investors and sent out ~500 emails, and this is a hot space for disruption, it's very unlikely that all of them are dismissing you due to gender; something isn't connecting. I's very easy to dismiss all feedback ("their feedback means nothing; they are rejecting me because I am a woman") just because you are soured by your bad sexist experiences.
Ask yourself these questions honestly: Are investors giving the same criticisms and feedback for saying no? Are there questions you struggle with in the pitch about your business? Is the value prop clear? Is the product demo well orchestrated? Try to examine all of the feedback you've gotten objectively, and see how can you improve the pitch. Find someone who is ideally involved in the venture community (e.g. as a partner, associate, EIR) that you can trust, that can give you brutally honest feedback on your pitch and business.
- Fundraising is hard for everyone. It's going to be harder for you. It sucks, but that's the truth of life. You are one of those pioneering women who are paving the path for others so hopefully in 20-30 years, it's not even an issue. It would be great if you didn't have to deal with this, but that's not the reality of the world. What doesn't kill your company will make you AND your company stronger.