Found it online! (a much longer quote here, its about half-way through)
I visited womanhood and stayed. It was not for the pleasures, though I discovered many I had not imagined, and many pains too. But calculating pleasures and pains was not the point. The point was who I am. Here the analogy with migration breaks down. One moves permanently from Sicily to New York because one imagines the streets of New York are paved with gold, or at least better paved than the streets at home, not mainly because back in Catania since age 11 one dreamed of being an American. Migration can be modeled as a matter of cost and benefit, and it has been by economic historians. But I did not change gender because I liked colorful clothing (Donald did not) or womanly grace (Donald viewed it as sentimentality). The “decision” was not utilitarian. In our culture the rhetoric of the very word decision entails cost and benefit. My gender crossing was motivated by identity, not by a balance sheet of utility.