Differences...his and hers

WOW, I really noticed this morning how much Little Miss A is like me and Mr. D is like his father. A bounces out of bed with a smile ready to play. (I am definitely an up and at 'em kind of gal.) D takes a while to open his eyes and get his bearings on his day before he emerges from his room. (Boy, is this his Daddy or what?) So, that got me thinking...do we have two clones of ourselves, or is this simply a gender issue? I'll have to start researching and get back to you on that. :)