It's a boy!!!?

On April 23rd I had my second child (a boy). The funniest thing is that he has slept through the night since we were discharged from the hospital. He only fusses when he is hungry (he eats a lot) or when he just wants to be cuddled a bit. My firstborn daughter was completely different ! She didn't sleep through the night until she was 12 weeks old and she cried almost all the time and was very discontent. How is it that two siblings could be so different in nature? He is such a calm child. Other than being peed on once or twice, he's a little angel. Anyone else experienced major differentces with their kids?