A: Deirdre, it’s great that you observe your twins closely, recognize each child’s unique temperament and abilities and try to offer stimulation to help their development.

There’s a wide range of what’s “normal” for children’s development at any age, as you’ve noticed with the differences between your twins. Although it’s natural to compare your twins to each other, try to appreciate each child’s uniqueness.. Just because one is born first doesn’t mean she should develop faster. And the baby who achieves some developmental milestones first won’t necessarily achieve all the developmental milestones first and is not necessarily “smarter.”

Since they were born five weeks early, they missed some time developing in utero. Therefore, you should expect their development in the first year of life to be about five weeks behind their actual age. In other words, you should expect your 4-month-old babies to act like 3-month-olds.

So what might you expect of a 3-month-old? Your babies should enjoy looking at you (which they are doing), smiling and cooing. They might also enjoy watching their hands moving and putting them in their mouths. It’s on the early side to be cutting teeth (the average age is around 6 months) but some babies start teething earlier. It’s also a little early to expect them to roll in both directions, but you should see that within the next few months. Also within the few months, you might see them grabbing their feet, reaching out for toys and passing toys back and forth between their hands.