Opinions of a 2 year old

This morning I woke M up and brought over the shorts and shirt she was going to wear. She told me, "No, no! No shirt!!" So, I opened the closet and pulled out a purple and green dress to which she responded, "Wear that Mommy! Purple dress!" G started getting very picky about the clothes she wore before age 2, and I thought it was just her. Now, to have another that just turned 2 doing this -- is it the age, personality, genetics?