I've only had both BPs out a few times. I've only let them touch each other a few times, but only for a few seconds. I understand that diseases and parasites could be spread from one another but both snakes are completely healthy. I don't have both out for long periods of time either. Just for 5 minutes at the most. I handle them individually daily, but when I spot clean the enclosures and change the water dish I'll have both on my bed, but separated on both ends of my bed and if they tried getting close I'd walk over and put them back in the spots I had them in.