Real Name: It will never be certain.
Age: It will never be certain and he merely made an educated guess, which he started to use for fact.
Birthday: It will never be known.
Blood Type: I have not the slightest, but believe no one other than the creators really knows.
Ethnicity: Earthling. (I am leaning close to European, though.)
Origin: Earth or L3 Colony. He might have been born somewhere on the L3 Colony and wound up on Earth at some point only to be drawn back to the colony or he was born on Earth and ultimately found L3 to be the place he was meant to be.
Sexuality: I doubt he cares about that, nor will care about it for a long while; he could go either way. (Though, ideally I see him with one of the other pilots.)
Experience: Give or take.
Sexual Abuse: Give or take, but I lean more towards unlikely.
Family: Catherine. (I see it as a spiritual family. She could be a biological or adoptive sister, or just plainly makes him feel a connection that only someone in one's family can produce.)
Mobile Suit: He could have left the hidden sword on the left arm of his Gundam, which he installed for Heero when fighting against Zechs, to use once he ran out of bullets. He obviously knew how to work a blade since he had the switch blade on his right one, but he seems more for working far away while in a mobile suit and up close when on his own. As long as he is piloting it, it is cool.