It's probably that the particular person that said that to you didn't agree with your portrayal of a female character. I've always been of the belief I can write any type of character if I try, I just like to stick to a certain type, namely [i]men[/i]. It's just what I'm comfortable with.

How does one even unrealistically portray a human being, anyway? women are people, after all. Maybe the person who said that, in actuality, didn't like your writing style, and attributed that to your character and by extension her gender. There are a number of factors to consider.

If you really are super competent in how a female sees things as you claim, and have even been role playing female characters your entire life, can you really ask for tips on how it's done? I realize you're embarrassed (as you said) to just talk to the person, but in all honesty I would really stop and consider the legitimacy of the claim being made. Even if you somehow have some writing issues you're unaware of, how would that be attributed to the type of character you role play as? it wouldn't. If that is the issue, just try improving your writing skills.