I would NEVER introduce two intact males, but I think allowing male siblings to stay together is acceptable. I have seen brothers get along great for a long time... and I have seen brothers get dominant with eachother and need neuters.

My friend's gliders are now 2 years old. They never have an issue. I think it's fine as long as they are introduced as young joeys and there are no females in their vicinity.

We have also had a couple purchase 2 intact males. One was mature before the other was introed. They got along perfectly, until one male died in an unfortunate accident. They now have the remaining intact male with two neutered males. All is still well.

Again, no female gliders in the household.

I have a friend that has 2 intact males together as well. Same as Allie,they have no other gliders in the house and have been together 2 years with no problems.

My intact male (Stitch) used to live with his brother (Lilo) at another hosue. Both intact, same age, never been seperated. The previous owner was told they'd be fine staying intact because they were related.

They were fine for 2 years, then one night they had a fight. Nothing had been changed, nothing done differently, nothing to 'cause' the fight. Male dominence fights can get nasty, Stitch ripped off his brothers ear and damaged his tail.

The lady split them up imediately and then tried to re-introduce, they couldn't be put back together. She couldn't afford to neuter and buy new cagemates for both of them so she reluctantly had to sell.

Stitch came to me with a tuft of hair missing from his head, nothing compared to the state he'd left his brother in. Within 5 minutes of getting home he was eating out of my hand and to this date he is by far my most bonded glider. Personality doesn't really have anything to do with it, if anyone asked me about him I'd say he was the sweetest glider, I'd never have imagined what he could do to another male.

It doesn't always take a female, it doesn't always happen straight away and it isn't guaranteed to happen at all, but for what the outcome could be I don't think it's worth the risk.