According to the Myers-Briggs Personality Test, I am an INTJ. The four letters each denote a personality characteristic: I for introverted, N for intuiting, T for thinking, and J for Judging. Amy shares the I and the J with me, but her middle letters are S and F (for sensing and feeling).
Specifically, it's hard to be an I and a J as a parent. Introverts are contrasted with extroverts, who think out loud and who draw energy from others. Introverts, on the other hand, think internally and draw their energy from alone time. It would seem, then, that extroverts have it easier as parents: they talk aloud to their kids more easily, and are more apt to be energized by a day with their kids and with other families. Us introverts, on the other hand, have to work hard to remember to engage in dialogue with our pre-conversant kids, and are often found absolutely drained at the end of a long day of parenting and socializing.
Those who are judging are contrasted with those who are perceiving. Here the main difference is between whether you like things sewn up or kept loose. J's like their schedules to be set, while P's prefer to keep them open. Parents, of course, have to hold their schedules loosely, because kids and days don't always go according to plan. A fever, a bump on the head, an emotional meltdown -- these common occurrences can take down a carefully planned schedule in an instant.
I wouldn't wish that Amy or I were different in either of these two areas. I do hope we'll continue to stretch ourselves in both areas for the sake of becoming better parents and retaining our sanity. For now, we'll try to channel our introvertedness and judgingness into ways that make us better parents, and try even harder to overcome our introvertedness and judgingness when it strains our ability to be good parents.