Yes, for small team (sub 10), I have seen high ratio of females/males, but for larger companies, it is impossible.

If you are hiring 100s, or even thousands of engineers you are bound to the supply of the market. Unless you do some straight out hiring discrimination, and refuse to hire males. Similar to some Vegas clubs (they wont let males unless they have a female with them). Good luck building a successful business with those values.

It is Econ 101 dude... or dudette (not sure you are guy or a girl)

P.s. I personally would love to have seen balanced genders (working for tech companies sometimes it feels like you are in the army), but that's probably a utopian ideal that is not going to be fixed in my lifetime.