Define Brahman

In one of my usual browsing sessions today, I came across a wiki article that raised a very elemental question.

What is the authenticity of the rituals that we follow today in the name of religion (Hinduism in particular)? More precisely, who is a Brahman?

There are copies of the Bible and Quran in certain museums but a complete collection of the Vedas/Shrutis is unheard of. Online archives of the same are of dubious authencity. Perhaps it is largely owing to the early origins of the same. However, the question remains as to the validity of our rituals and ceremonies.

Is a Brahman caste a result of heredity? Or was it meant as a class/distinction granted to meritorious students in the gurukuls? It is a known fact that not all Brahman children are brilliant and vice versa. Therefore, how is it fair to deny the right of our scriptures to our meritorious counterparts simply because they are not conferred the Brahman caste?

The learning of the Vedas was a closely guarded secret for ages. The same has been passed from one generation to the other mostly by word of mouth. Granted that such individuals were learned men of the highest order. Questioning their integrity is definitely a no brainer but what about the interpretation of the shrutis from one generation to the other?

It is an accepted fact that the hand that rocks the cradle rules the world. If Brahman is a product of heredity, why then were Brahman women denied the right to scriptures by the so called brahmins? We know for a fact that women like Gargi, Maitreyee, Khana and others were conferred the Brahman title and elaborate thread ceremonies were performed for them by the rishis. So where did it all change and why? If Brahman is a result of an unbroken line of male descendants and progeny which undoubtedly is a factor of two (of which one is deliberately kept ignorant), what is the guarantee that the resulting gene will be of the highest order?

Coming from a "unbroken" Brahman family where women are treated equal if not superior to men, I have had the privilege to question our roots. I find it depressing when people are rejected as proper alliances in our family simply bcoz of their caste. I am a devotee of Krishna and find myself increasingly being drawn to the teachings of Sanatana Dharma. Is there a clear answer to all my questions which will resurrect my complete faith in the caste system?