I believe, because it happened once in my life.
Pheromones it may be, but, it seems the feeling was mutual even though it took a while to express it.
We were both Aspies.
I was doing a part time inventory job when they brought in a new guy and put him on the same row
in the store as myself and a few others.
It wasn't looks or lust at first sight. It was only a matter minutes when I knew I liked his personality.
Just like a magnet I was attracted... (pheromones)? Probably.
Lunch time came and we all went to the cafeteria where the two of us were just pulled together
picking out what we wanted and went to a table together.
How do you know when it's love? For us, both being Aspies, I think immediately feeling comfortable
looking each other in the eyes as we talked.
Yes, it was the eyes that I found physically appealing.
He was the first man I felt in love with and the first in, well, you know everything that follows.

It was a long term relationship of many years.