I have one of each also. My girl is 6 years and my baby boy is almost 11 months. We had him neutered at not quite 5 months and he still squats to tinkle in the house. Until this past week I had never seen him lift his leg but I think Soph has been teaching him bad habits
. She's actually my leg lifter and will sprinkle every 10 feet when we're out on a walk. Our last walk gulliver was following along behind her and every time she lifted her leg he'd go right behind her and do the same. I firmly believe that getting them neutered early definitely helps.