When I got my second hedgie, he was two months old and my first was about 5 months old. I wanted to see if I could put them in the same playpen with me, so I could have them out at the same time. When they encountered each other, they both balled up and huffed at each other, and Jack's visor got caught on Spike's visor. I was worried that Jack (who only has one eye) would get injured if near Spike again. So even though neither showed aggressive behaviour, even their defensive behaviour can have dangerous effects.
If I have them both out at the same time, I use my legs as a barrier between them. They will stay on their respective sides of me and there's no contact to worry about.
I've heard some pretty nasty stories about males attacking each other, so I just wouldn't risk it.