"DNA and your upbringing"
for this I actually like to use the argument used for abortion by Marry Ann Warren, the 5 criteria to be a full-fledged member of a human moral community (which is communication, self-motivation, self-awareness, rationality, and consciousness). What I concentrate most here are to do everything consciously, and be self-motivating.
note: though this argument in the reasoning for abortion/applied as a universal law, has some shortcomings, I actually agree with this and think this should be applied to some extent.
note2: I use the term "consciousness" here as not BE conscious (since we all sleep, and wouldn't want to be called not human just because we sleep! but instead use this as to DO conscious things. in another words, antithesis to subconscious rather than "not conscious".
what you said is true; if everything is determined by DNA/Genes and our upbringing, yes, we don't have free will in my opinion.
(allow me to make a few modifications in the vocabulary so that I can flow your argument with mine.)
what you're saying is that if DNA is determining our actions, it is our Genes, and if it is our genes, it is our instincts, and in another word, it is our subconscious (whether it be desire for sugar, protein and fat, or to procreate or altruistic acts). So we need to use our consciousness to control our subconscious.
When you say upbringing, I will expand this to government, society, media, entertainment, advertisement, parenting, and every other external motivation. And we must control this and not allow any of this to be a motive and reason for what we think and do, so we need to be self-motivating, do what we think is right from our own selves and rational, rather than anyone else saying.
So I summarize,
If we are determined by DNA and our upbringing we do not have free-will. Agreed.
If we are not determined by our DNA and our upbringing, we do have free-will.
Let us do things out of our own consciousness, and be self-motivating.
Lets get to work and earn our free will shall we?