I agree with advice and comments above, and have had the same experience as Lynn. I have never heard of litter syndrome either, and my experience has been a positive one. We brought Bulldozer and Blossom home together, and potty trained them together on the same schedule, we had them in a double crate at first, but then switched them to separate crates right away, because Blossom wouldn't leave Dozer alone, he just wanted to sleep, and she wanted to play all the time, and would jump on him, lay and sleep on him, and she would chew on his ears playfully all the time. Dozer couldn't sleep, so we separated them and it was fine. They were so funny because they would sleep in the exact same position all the time and they still do this. They also like to lick each other through the crate. They do prefer to play with just each other when we are around other dogs, but we did socialize them with other dogs, people and kids from day one, so they do love and get along with all, and they are both bonded to us. They have different personalities, Blossom has much more energy and stamina than Dozer, but I think this has a lot to do with his many allergies. Blossom loves to walk all the time, and is much more active than her brother, Dozer prefers to just sleep. Lol, but they both love to cuddle or snuggle, Dozer just likes to do it all the time, and Blossom will cuddle when she feels like it, and when she's ready to sleep. Having two dogs is definitely a little more work, but not that hard, we keep them on the same schedule, and they are great company for each other, and having two bullies is definitely more fun. I don't know if it makes difference to have the opposite sex, I have heard that two males can be aggressive to each other, and two females can be jealous of each other, but I have no experience with this. I know of any people who have two males or two females and they are fine. Congratulations, and enjoy your babies.