If 30 years out just 1 in 100,000 men are doing this at a given time, it'd be over 100,000 male births annually on the planet.
Personally, I think this will, in modern historical terms, be the most significant catalyst in equalizing the genders. But I don't expect feminist groups to embrace it with open arms.
You'll have men that were born as men, who want to be men / identify as men. I'd expect that to be a smaller share of the male birth number. Then you'll have men that were born as men, who want to be women / identify as women. That will likely represent the far larger share of the male birth number.