Moms and Dads, if you have more than one child, have you noticed any differences between (or among) them in personality and temperament? I'll bet you have. I certainly noticed the differences between our daughter and son when they were growing up. Our daughter was five years older than our son (in fact, she still is). She's outgoing, compassionate, traditional, and tends toward obsessiveness in her attention to detail.
Our son, on the other hand, is somewhat reserved, rational in thought, open to new ideas and directions, and flexible as far as details are concerned. If you met them at the same time, you would notice some differences right away (the more obvious ones), but the important (less obvious) contrasts would take some time. That's where you parents have the advantage with your children. You have the time to observe, analyze and discern the more subtle personality and temperament shadings.