Sometimes I'm amazed by the confidence of people that deliberately have an only child. They seem supremely sure of their ability to raise a human being correctly on the very first try.
I have 3 children. If there's a mistake that I didn't make with one of them, it's not my fault. With the first one, a very easy-going child (boy, do I wish I had appreciated her more at the time), I was trying hard to be a "cool, hip" mama. Not easy when you're a natural-born geek.
She is cooler than I, currently a novice with the Sisters of St. Joseph, Third Order of St. Francis (SSJ/TOSF). I am in awe of her skills with people, and her competency with managing conferences and big projects.
With number two, I got into the natural, organic earth-mother phase. The theory was that by feeding kids natural foods, starting with breastfeeding, you would produce a mellow, holistic little human.
So much for theory. He was a whirlwind of energy, who leapt out of bed at dawn, and didn't quit getting into everything he could reach (and a few things he couldn't) unti, at the end of the dayl his eyes rolled back in his head, rendering him instantly unconscious for at least 6 hours.
I resorted to stuffing his face with food, plunking him down in front of the TV, and taking the few minutes that his attention was captured to get stuff done.
Amazingly, he slowed down as he aged. He is not now hyperactive or attention-deficit. In fact, he has lately discovered the pleasures of lounging around and arising late.
Number three was quiet, but a whiner. Her favorite tactic was noisy passive resistance, accompanied by sulky looks. She was a major league picky eater, subsisting on vegetable plates and soup, supplemented by various refined grains (all three hated whole grains).
She also changed as she aged, eventually entering college, and, at the end of her freshman year, joining the Army National Guard. I was dumbfounded. I would have taken bets on her washing out early.
I seriously underestimated her. Despite a serious injury in boot camp, causing an 8-week experience to balloon to over six months working to re-hab the injury, she persevered. She is nearing the end of her committment, slightly less than a year to go. Her unit was sent to active duty last year. She missed it, due to advanced pregnamcy (8 + months). I am crossing my fingers that she will not have to be deployed.
Younger children are a chance to try again, this time without the mistakes. Unfortunately, the next time, you make different mistakes.
Younger siblings are the equivalent of a parental "do-over".
And, surprisingly, my personal input efforts may not be as important as the inborn temperament in defining who that person develops into. Shyness, ability to relate compassionately to another, tendency to brood or to laugh things off'; these are all some of the aspects of personality and character that may be inborn, not nurtured.