was he “born thief”?
heh
The odd thing is, that really is the relevant question, not because the answer is self-evidently "no", but because, in light of the Fall, the answer to both "was he born thief?" and "was he born gay?" might both be "yes".
None of us are born having committed any particular sins -- we have not stolen when we are born, nor committed buggery, nor fornication, nor murder, and the like nor even the more nuanced underlying sins of covetousness, lust, wrath, or the like, but we are all born into the consequences of Adam's transgression. In that behavioral sense, no, the thief who objects his thievery is inborn would be wrong. But, that we might be born with an inborn besetting temptation is quite likely -- I suspect my own bad temper is inborn, but I will not attempt to argue "God made me wrathful, therefore wrath isn't a sin because I was born that way." The "born thief" may well be right that he was born with a besetting temptation to covetousness, indeed one so strong that without grace from God, struggling with it on his own, he "can't help himself" from stealing.
That a besetting temptation is inborn does not make yielding to that temptation not sinful. The correct answer to "I was born gay" is not "No you weren't", but "I'm sorry you have to struggle with temptations to the sin of buggery."