Can a portfolio be properly balanced with everything in one sector with a mix of value and growth positions?

I'm following the old "invest in what you know" tactic and sticking with drug development. I thought I would split my portfolio between big pharma as"value stocks." Smaller bio-techs with only a handful of drug candidates I see as a type of "growth stock" that is perhaps overly speculative.

I wanted to ask for the community's recommendations if this was a good way to structure the portfolio. Is that an effective dichotomy? Am I not diversified enough by sticking to one industry? Coming up to the end of my second month here and any input would be appreciated!