If you call those comments "sexual harrassment" you're the one making yourself feel miserable. Watch streamers like kurolily, jooygirl, and legendarylea, among many others and learn from them.
Legendarylea gets a lot of comments about her body, she doesn't care she is just full of energy and fun and that makes it better for everyone involved. Occasionally she'll poke fun at the commenter with the picture of bouncing tits (little birds), which is hilarious, or the one with blue-footed boobie birds.
Jooygirl seems to have good moderation in place, I've only seen her once call out a commenter that asked her to strip, and she didn't get angry, just told him to at least make an effort to be more witty.
Kurolily gets occasional comments, but mostly compliments that she is pretty (and she is), and she doesn't seem to be bothered by the compliments, and why should she be? Her attitude is also very positive, and she tends to ignore the odd rude comment.
You know it's the same when I play Hearthstone. If I feel crappy all I see is people abusing me when they say "well played" (they are mocking me), or "thank you" (they are making fun of my bad play).. etc. It's all in your mind's eye.
Besides there's lots of kids on Twitch. What do you expect of adolescents and young men? Being rude is not ok, but at the end of the day if you want to get a positive audience you have to be the example. I would bet that in fact jooygirl doesn't get a lot of sexual comments because she is so energetic like legendarylea, and she is always smiling and having fun. That is your best weapon against those type of comments, because it creates a connection and it's hard for people to obectify someone smiling.
And no it's not easy, but hey I'm not a streamer. You're the one who wants to stream as a woman so deal with it. Asking for a whole culture of overt sexualisation and a porn industry that is becoming casualized in our society is a big stretch. You're the only person who can make the change in your stream.
If you're not witty with replies to the comments (it's a skill, I'm usually bad at coming up with witty answers), then do the legendarylea thing and make some funny pictures. If you can't keep up your mood, then I'm sorry but streaming is not for everyone.
With all that said I completely agree that it is a problem, but it is not at all particular to Twitch. It's a much larger problem. How do you think I feel when I go to YouTube as a guy, and I am assaulted with thumbnails promising me women in tight shorts showing me their buttocks, etc.? None of those videos are flagged because they are supposedly educational, or "fail compilations" etc. I am being shoved sexual content in my face continually day oin, day out, even as I try to quit pornography.
It's a much larger problem. So all you can do is take responsibility and change your own attitude, because if you wait for the world to change you're gonna feel pretty crappy for a long time.