i dont like the term "full-time" and dont see it as relevant for me, as I immediately began consistantly presenting my gender as female as soon as i learned how to do so, and my gender expression has always been genderqueer or androgynous (and as such there has never been a need for me to be "part time", as i have always worn whatever clothes, accessories, make up, hairstyles, etc I wanted to). That being said, I am a trans female who has been consistantly presenting her gender as such for almost a year, without hormones. I am intersex, and pass well. sexual biology varies immensly amongst humans (and other species) and i imagine passing is more difficult for some without changing their sexual biology via hormones, but i view gender as being social, basically.