If you’re like most people, you probably said to yourself at least once during your childhood or teens: “I’m never going to behave like my mother (or father) when I grow up.” Such thoughts would enter your mind especially when your parent treated you in a harsh manner, embarrassed you, or ignored you.

And now you may find yourself behaving in the same bratty way toward others. How could this happen? Much to our chagrin, it's quite common to have some of the same negative traits as our parents, despite our best intentions to avoid them.

Some people attribute these similarities to their heritage: "I'm Italian," they'll say, or "I've inherited my father's German stubborn streak." Others claim that all these behaviors are just learned -- if you hang out with screamers, you're going to be loud yourself. If your family doesn’t hug one another, you’re not going to be very affectionate either.

It’s true that environment does shape our personalities to some extent. Culture and family life certainly affect how we behave. Kids imitate what they see and respond to what they’re rewarded for. For example, parents who value education and praise good grades typically have children who are better students, regardless of IQ levels.

But environment doesn’t explain everything. Despite parents’ efforts to raise responsible, conscientious citizens, some children will not turn out that way. Similarly, it is not unusual to see well-adjusted individuals who come from a highly dysfunctional family.

Research on twins has shed light on the role of environment vs heredity in determining personality. Each set of twins raised together drink the same water, eat the same foods and watch the same TV shows. They go to the same schools, know the same peers and experience the same discipline style from their parents. In other words, all twins (who are raised together) share the same environment.

If environment is the key to personality then we would expect identical twins to be no more similar to one another than fraternal twins. But that’s not the case. Research has shown that identical twins (who have exactly the same genes) are more similar to one another on many personality dimensions than are fraternal twins (who share only 50% of the same genes.)

What’s more, identical twins who were adopted by different families are more similar in personality to one another than to the separate adoptive families in which they grew up!

This means that heredity has a big role in how you turn out. But it’s not simply a matter of “inheriting” your mother’s bad temper or your father’s drinking habit.

Experts believe that what you inherit are “temperaments.” Temperament is a predisposition to react in certain ways. It appears at birth or shortly thereafter, and tends to run in families. This explains, for example, why certain breeds of dogs are more aggressive than others.

It’s the same with people. Some babies are more active than others; some are more distractible; some are more easily startled.

These temperaments help determine not only the kinds of experiences that a growing child seeks out -- for example, one who needs a lot of stimulation will take more risks -- but also, how others respond. Thus, a child who is calm will tend to elicit different parental reactions than a child who is more excitable.

So how does all this figure into your parents’ inner brats and your own? It is quite likely that you have inherited temperaments from one or both of your biological parents. If your parent gets angry easily, you may too -- but not because you inherited your parent’s anger. It is because you inherited a sensitivity to irritation, or a predisposition to react quickly to situations. These in turn make you prone to impulsive behavior such as angry outbursts.

Before you get ready to use this as an excuse for your next temper tantrum or drinking binge, keep in mind that you do have control over how you channel your inherited tendencies. For example, a person who needs a lot of stimulation and novelty might end up as a criminal who takes risks -- or as an inventor, a CIA agent or a professional entertainer. Someone who is innately cautious might end up as an underachiever -- or as a quality-control specialist, a researcher, or a brain surgeon.

Thus, even though temperaments are inherited, inner brat behaviors are NOT inevitable. The very traits that get us into trouble are the same ones that can be put to constructive use. With a little creativity you can nudge your inner brat in a more positive direction.

Visit http://www.innerbrat.com for more information, and subscribe to her free, monthly Inner Brat Newsletter.