Note the words 'outward expression' in my post. Clothes. Hair. Makeup. Gestures. Ways of speaking. These are outward expressions.
In current culture, the 'typical' gender expression is that long hair, makeup, high heels and skirts are for women. But long hair, makeup and a skirt is standard for men in Masai culture. Or the court of Louis XIV - where they also wore high heels. Roman men wore a dress and makeup. In Ancient Greece (pre-5thC BCE) long hair was a marker of a free man or woman, and short hair was a sign of slavery. In Sparta long hair was for men and short for boys.
This is cultural. It varies across time and place. It is not innate.
And in all cultures, there are subculture. For example men who are goths, emo, punk are more likely to wear makeup than men in the general population.
And because being gay or lesbian has often been either illegal or at least disapproved of or outside 'mainstream' society, people whonare same sex attracted have tended to form subcultures. Which - like goths, or Californian valley girls - have their own cultural markers in the way they dress, gestires they use, patterns of speech and slang etc. For example a lesbian in the mid to late 20th century UK was probably more likely to wear a suit and tie than the average woman. But so did Judies (the female equivalent of Teddy boys). Both wore certain clothes because of pride in their culture, a way to identify themselves to each other, and because that's what their friends and cultural influences did.
But putting on a tie doesn't make a woman a lesbian. Nor does being a lesbian make a woman put on a tie.
Same-sex attraction is innate. It's nothing to do with what hand gestures you use, or what you wear, or whether you like ABBA. It's not about subverting cultural gender norms - although some gay or lesbian subcultures may tend to do that (although in doing so, that become a gender norm of its own) - it's is purely about who you are sexually attracted to. That remians true across all cultures.
And it's measurable - in a way that transness is not. You can objectively test physical sexual responses. You can't test a feeling of being the opposite sex.