It's a job for people who know about maintaining gardens. In a way it is a manly job, as you are cutting down stuff and pulling things out with your bare hands.
I think it's a great job. You get to be outdoors and when you finish your work, you can actually see that you made an improvement. What does this have to do with being gay?
It is good exercise and nothing to do with gender. My great nephews do it and are building muscle and both happen to like girls, even if they were gay it wouldn't have anything to do with the job.
No, what would happen is, advanced ageing would occur. Your sexuality would stay the same but you would start wanting to rent an allotment yourself.
Where in he world did you get that idea?