I skipped grade 4, in an organized acceleration. It was never an issue, I am a female and people say it is harder for boys. I do not know. I do not know any problems for the boys that skipped with me.
Although I didn't get a driver's license until grade twelve (june birthday), and had skipped another year in high school, that part didn't really bother me. I don't think I could have dealt with staying behind and having the curriculum slower. It was hard enough as it was. By grade nine I tested in the top tier of the high school in math. There wasn't any challenge. Teachers dealt with me in that I didn't have to come to class and I missed 56 days in grade nine (my history teacher kept track). Socially it probably is harder for a boy. But my mother wouldn't let me date until I was 16. And that was hard, but I dealt with it. It didn't scar me for life. And it won't scar a boy, except I do see a lot of nerdy "boys" who couldn't get the girl in high school have serious complexes. They make millions and have relationship issues.
That was anecdotal, but being a young woman on Wall Street, I dated a lot of those. There is one famous guy... tales out of school. But I think that is an issue for boys. They make money but never trust the girl likes them for them. I am being very serious about that. But I think that is better than having them underchallenged and underachieving.
Take your pick on the lessor of evils.
Ren