It is not black or white, it is both.

If you’re stuck at that level of understanding then you know little about the function of the other 90% of the brain we never use. Really embarrassing.

While I’m sure a good portion of each of us is predetermined by genetics, environment, parenting, and random chemical interactions, I’m still confident that most of us have free will.

Every choice I make is pre meditated.

If you are to argue that introspection, analysis and conclusion are proof of free will, I could argue that the fact you arrived at these conclusions, the whole way your brain interprets data, is a result of prior experience or present biology.
Also, without wishing to be disrespectful, this was a question asked with the highest scepticism and intellectual honesty in mind. I always value an insight into others worldviews but I don't think writing any credit off as God is credible (Google argument from ignorance)
On the same subject the quote from Hitchens above (one of my idols- I've only disagreed on two points in everything I've heard from him) I feel this again doesn't deal with the issue. He was gifted in many ways with the ability to see more clearly morally and more courage to say it then anyone else I'm aware of. However, he arrived at those views because of the life he had experienced.

We have a good understanding of how the brain works now and this being the case surely the only logical conclusion is that No one has freewill or the ability to make choices because it's all based on physical processes that are moulded by exterior stimuli. If you dropped any brain into Hitler's baby and gave it the exact same physical and biological data then you would have another Hitler. Even me seeing this and saying this are a result of my knowledge and inclination, both of which are the result of exterior stimuli

I believe in order to discuss moral experiences as right or wrong-we must determine rationale/logic is determined in a design of intelligence. Otherwise how would one trust what they know is actually knowable and truth can be determined by it. It would not make sense unless we can determine absolute morality exists-not of ourselves but within the context of Design.
Absolute morality exists because I would not voluntarily desire to be murdered therefore it would be morally wrong to do so to another human. I would not voluntarily desire to be stolen from therefore absolute morality of Do not steal could be applied. As with all 10 commandments.

"Yes I have free will; I have no choice but to have it." - Christopher Hitchens

I think that we are shaped by all influences around us. Leading a form of logical thinking. If ones mind isn't lazy by following the crowd, then freely think, analyze and change can occur.

Yes we have free will as I see it. However, the skillfulness of our choices is limited to the developmental stage we have reached at any given time in our lifespan. Unfortunately, some people in their 30s, 40s, 50s, 60s and so on, never grow up and remain children and the decisions and choices they make throughout their lives, reflect this lack of maturation.

If we do not have free will and are not responsible for our actions can choice exist?

Conservatives inherently are conservative because they believe in free will. Socialists in contrast are behaviorist who do not believe in free will and this is why they practice victimology. And can justify the argument that all those who are better off are guilty of cheating or being the unjust recepients of circumstance.

Genetics and experience and parenting certainly can affect how we perceive actions of others, but so also can individual introspection, thought, and individual learning. It is the "individual introspection" aspect that eventually makes a mature person out of a juvenile. I guess it could be argued that all individual introspection/maturation exists because of genetics and experience--and I would say that such an argument could not be provable either way--but encouraging such a view could very well have the effect of decreasing individual introspection, thought, and even effort.

I have two questions that might help you flesh out your thinking, and a tangentially related joke:

1. What is "the right thing to do"?
   My answer (which may differ from yours): It is the thing that strengthens your relationship with God. Your view seems to be materialistic (in the philosophical sense) so it's not clear to me what "right thing to do" could mean from your viewpoint.

2. Why would you "judge people"?
   I would say we should judge people's actions, to determine if we should trust them, and/or how we should try to help them. However, ultimately only God judges the person.

Joke: Two philosophers walk into a bar. The first one orders a beer. As he pulls the beer, the bartender says, "Do you believe in free will?" He responds, "I want to, but I just can't! There's not enough evidence!"
As soon as the bartender puts the beer down, the second philosopher takes the beer and drinks it.
His friend asks, "Why did you do that?"
He replies, "Either I just had free will, or I just got free beer!"

Nature, nurture... yada yada. We are the result of the choices we make. I know I am better equipped for this by virtue of breeding and upbringing. At the same time grand obstacles lay in my path to hinder any success. I still got over, under or straight through them. My Mom taught me, young, I was the only one I could rely on.

She also taught to always look for the best in others but not waste time on it. It usually isn't there. An old high school freind is still shaping surfboards, smoking dope and lives in his Mom's house, she passed some years ago. Is he happy? He just let things happen. Went with 'the flow.' Maybe he is, I don't know. Still his choice. A 60 year old teenager. He, Tony, always made fun of me because I liked to work. He hates choices. I live for opportunities.

I will see him this Spring when I go West for a visit. I don't need to call. I know where to find him. That is Tony's choice. He has no idea where I live.

Are long as one's brain is functioning normally (no mental ailments of the sorts), then one is responsible for their actions and thus does possess free will.