I am not adopted, but my "father" wasn't really my biological father, so I can some what understand.
Anyway, I think that if someone is adopted they should be told at a younger age, I wish that I was told this guy was not my actual father, because I never felt comfortable around him in the first place, but now I hate the man because I had to live a lie for almost 14 years.
But thats me, I hate being lied to, I think its one of the worst things you could possibly do to someone, especially if you're trying to be a good parent. The truth should always be spoken, it builds comfort and trust, besides if you don't lie, you don't have to worry about slipping up, or in my case, I found out because my last name wasn't the same as the one on my birth certificate, so when I went to enroll in Junior High (I don't know why it took so long for them to catch it) I found out that my real father had been told to leave my life.
Even though my real father was told to leave because he was a drug abuser, I think it would've been better if I had known that instead of believing that this other man is who gave birth to me, because now I have no respect for him.
(On a side note, 50th post)