I fist donated sperm when I was about 17 till I was about21. Then I re started st about 26 till I was about 34. I re started when I was 36 till I was 43. Not done it since but would like to re start, as I'm wasting it masturbating and could be helping people again ..
I have to admit that I've never liked the idea. To just create a kid in a lab is...well it just feels wrong. Also by donating sperm, you have no idea who your own children are and they don't know who dad is. It's a sad thought.