Adult male cockatiels lose their pearl markings at about one year in age. At this time they look like a normal gray bird. The hens will keep the pearl markings for their lifetime .
There are no distinguishable markings between Male and Female Pied birds. There can be a lot of light or white, "a heavy Pied" or they can just have yellow on the back of their head, "a split pied".
Lutino babies, hens, and adult males all look alike. If you look close, you may be able to see strpes on the tale feathers of the babies and the hens that will not be on the adult males. Both are born with red eyes.
Some Dominant Yellow Cheek Tiels have a much lighter cheek patch and some look like pastel face Tiels. They are easy to ID, if they are the light yellow color.