Still, my life experiences tell me that biology is a more significant factor in shaping us than environment. You can grow a square sided watermelon in a box, but it is still going to be a watermelon. Our lives can pressure us to conform, but to a larger extent, we will still be the same person.
Good points, although I feel as through, personally, you are over simplifying the environmental factors that play into shaping our personalities, as I believe that the "nurtur" which really means the environmental factors such as our Socioeconomic & finacial status, as well as oir physical environment (city/country/apartment/house big/small family) have a major impact on our mental wellbeing/state of mind/our genes/personality, yes biochemistry is important forsure, but I think it plays the smaller role. When we are babies(even as fetuses) our brains develop begin developing our neuro network and nervous system, which as you may know is the way information travels thoughout the brain and body, Neurons recieve and transmit messages from one part of the body to another, controlling reflexes, touch, smells sight, storing information, to solving xomplex math problems, developing our personalities, this is all done via neurons communicating with each other, literally everything we do is a direct result of the function of this system.
So everytime we experience something particularly in our first 20 years, the most active being between prenatal to puberty, creates neuro pathways, these pathways grow rapidly then begin trimming unused pathways.
So the exposure to external stimuli really shapes us and our earliest experiences Infact shapes us greatly, biology does play a role, when you get into hormon levels and dopeamine and serotonin and oxytocin etc. But external factors greatly effect how and when those hornones are distributed. That is called epigentics (when gene function gets altered as opposed to changing DNA) so like alcoholism/addictions is the result of epigenetic hereditary not genetic hereditary,
Our personalities we feel like are who we are interenally and thatbwe are wired that way. For the most part its true, but I believe that is because our personality is the core of our neuro network, which is shape by the fabulously complex and nuanced interaction of external simuli and our nervous system from the moment it begins to develop in the womb.
Anyway, our sex hormones have two very important stages of activity that effect our development
Once during prenatal development where we develop our primary sex characteristics (development nod either the vagina or penis) and in puberty, development of secondary sex characteristics (breast, or deepening of voice or certain muscels etc).
The development of male sex characteristics is the result of high levels of testosterone at these key points (testosterone is the strong hormone out of the two, we essentially all start out as female, but depending the on the amount of testosterone released determines whether we develop a penis or not)
As far as gendee, we begin the socialization process at birth or now with modern technology we xan know before birth the sex characteristics and will start the socialization process before the baby is even born, this socialization has a profound impact on our development. Also depending on the the external factors the mother was going through during pregnanc, possibly even at the time of conception, can effect the way in which the body releases chemicals, which would effect how the fetus develops.
Basically I belive its not exactly 50/50 I think rather its more like 30/70 in favour of nurtur.
As external factors can effect how our bodies send and recieve chemicals etc. Etc. Etc.