Help your son come to terms with who he is.
Then he'll be able to walk into the women's department and buy whatever it is his heart desires instead of feeling a need to sneak around and steal it.
GLAAD: Leading the conversation for LGBT equality | GLAAD
PFLAG: Parents, Families, & Friends of Lesbians and Gays
Those are two excellent resources to help parents of children who are wrestling with gender identity.
I wish you both the best!
Sincerely,
Pfrog!