I'm a vegetarian but not by choice, I've been a veggie from birth. Any meat, fish or eggs that went in my mouth was immediately spat out or if Mam managed to get me to swallow I threw it up. My system just couldn't cope with these foodstuffs. Anything else, fine.
Our doctor told Mam that I HAD to eat meat etc or else! She tried and I tried but to no avail, meat fish and eggs made me sick.
Much to my surprise, I found at the age of 28, that I could eat an egg, (hard only), without being sick.
I'll be 50 on June 12 and I still try occasionally to eat a small piece of meat or fish. To date no success.
I can cook meat and fish, smells great, but put it in my mouth? No thanks, until the next try.

Mike