Back in college, our behavioral science classes asserted that keiki are more influenced by nurture than nature. After becoming parents, however, many of my friends came to believe that personalities are more innate than developed.

Whether the chicken or the egg came first in this ongoing debate may never be proven. However, I do know that our two little ones are already displaying their differences:

EATING

Keiki No. 1: Fell asleep instead of eating after birth. Didn't cry hungry until hours later. Later, refused to eat anything pureed, leaving us with plenny leftover jarred baby food. Eats neatly and methodically. At a recent potluck she was yet again the last to finish, causing another mom to remark, "She must really enjoy her food!"

Keiki No. 2: As soon as he was born, he wanted to eat. Ate every three hours until almost 7 months old. Consumed such a copious amount of introductory solids that he upchucked. Eats quickly and messily, causing us to invest in a handheld vacuum and Costco-size packs of paper towels. Devoured so much jarred baby food that the cashier asked me, "Is this all for one baby?"

DRINKING

Keiki No. 1: Loved the bottle. And not just any bottle, but one specific type. After a year and a half, finally transitioned to a sippy cup (but just one particular kind).

Keiki No. 2: Didn't care what he was given as long as he could extract liquid from it.

SLEEPING

Keiki No. 1: By 3 months, she slept through the night. Had two naps until age 2, and continues to nap once a day.

Keiki No. 2: Would probably still be waking up every three hours had we not utilized the "cry it out" method. Even as I write this, he refuses to nap.

INTERESTS

Keiki No. 1: Gravitates to the stuffed animals and anything cute. Little interest in building blocks but loves books and puzzles.

Keiki No. 2: Toy vehicles, balls and anything that moves or makes noise. Little patience for books but taught himself how to put together building blocks.

PERSONALITY

Keiki No. 1: Takes in the situation before participating. Focused, observant and able to sit still.

Keiki No. 2: Literally jumps right in. Sociable, eager and on the go.

Only time will tell whether these traits will hold in the future, and we may never truly know how much was inborn versus influenced.

In the meantime, my kids' idiosyncrasies remind me that everyone is unique and to be loved for whom they are, nature versus nurture notwithstanding.