Generally I would agree with the others, same sex dogs tend to have more issues with each other... Like Zeke and Eli did. Zeke didnt like Eli from day one, but we were able to manage it. He got used to him being around, but didnt like it when E over-stepped his boundaries.

On the other hand.. Take Bunny and Mia or Bunny and Treo (formerly Lily, our new addition).. From day one Bunny hasn't had ANY problems with either of them. She loved Mia.. they played and played and played. She plays with Treo as well... maybe not quite as much, but she still does. They all three cuddle on the bed, etc. No issues what-so-ever.

I'd say generally, yes, but it's varies dog from dog really.