this is NOTHING to worry about!! At age 2, they just want to copy everything that they see...my son LOVED to apply makup at that age, and i would brush some powder on him...he loved being spritz with body spray that i used. It was a "I want to be closer to Mommy" thing...he is a well adjusted little boy, who is aware of his appearance now....he likes to look nice....in a normal, I care about myself--sort of way.
Plus, at this age, they really like new things...gyrls clothes are so much prettier, and brighter--so more fun....fascination with bras and such are just that! It's something new and he is learning his world around him.
Research has shown that boys who learn about their feminine side are better caregivers, better fathers, more compassionate, get into less trouble and are more loving.
Biologically, boys do not start becoming "more like Dad" until age 5 years! So playing dress up and tea party is all just fun and games, and has nothing to do with gender roles.
At age 2, he is still learning about the world, and when he chooses to do these things--you can say things like "silly--thats your sisters!" but still let him explore and learn....You actually could make him very self-contiguous about liking things that others would consider "girly"--like him being concerned about his appearance, liking to cook, or liking to play with dolls (which could lead to a career in fashion, chef, or daycare)
Do not worry--people are born with their sexual preference, they do not learn it from wearing pink, playing with dolls, or even by a gyrl playing with truck, and love digging in the dirt!
Also, think of it as an opposite--if your two year old daughter wanted to wear daddy's t-shirt and shoes, would you be as concerned?