Fundamental concepts
Your children will look like one or both of their parents. That is genetic; their looks will be based on what they inherit from your genes. But their personality will not be genetic. Instead it will be formed by the programming of their subconscious mind
Before I go any further I would like to say what I think your personality is. It is what other people perceive about you by way of your consistent behaviour, including all of the small things like the way that you smile, whether you smile a lot, how positive your attitude is, how happy you are, how friendly you are, and a whole lot of other personal attributes that I am sure you can think of.
If you want to have a great personality you need to consistently behave in such a way that you display these personal attributes all of the time. So, the question becomes more about what determines your behaviour than anything else.
Your personality is determined by your consistent actions, which are determined by your consistent thoughts, which are impacted greatly by your beliefs about yourself and the world you live in.
Quite simply you become what you think about most of the time. Your success or failure in anything depends on your programming, and that comes from what you say when you talk to yourself, and what you accept from others. The brain simply believes what you tell it most, and what you tell it about yourself, it will create.
I had already started doing the research into personal development when I saw the British documentary, and in the years following that documentary these fundamental concepts were also starting to take shape for me:
A child's brain is not pre-programmed for inherent behaviour. We do not inherit our personalities from our parents.
During the early years of a child's life, particularly the first five years or so, the child's brain is like a sponge, soaking up everything in the world that the child experiences.
Your beliefs about yourself are formed by the interactions you have with the world around you and especially the significant people in it during this time.
Children are too young at this age to critically evaluate interactions with other people and simply automatically accept everything without evaluation.
Your beliefs about yourself are well formed by the time you are around seven years old.
A child learns to do nearly everything by copying.
A child sees, responds to, and copies the behaviour of the significant people in their environment. Usually this is their parents.
Your personality is therefore usually determined by the behaviour of your parents and any other significant people in your life and especially by their interactions with you.
Your personality is at least substantially formed by the time you are about seven years old.
If you believe these things to be true, then you should also understand that, as a parent, you have an opportunity to exercise substantial control over the personal development of your children. Their personality and attitude to life is going to be determined mainly by you.