This question has gone back and forth a lot, and the data says: both! The overall development of organisms depends the sum of the effect of the genes, the environment, and the gene-by-environment interaction.
In conclusion, to predict human behaviors and personalities, we need a new zodiac system that accounts for multiple hemispheres, precipitation, elevation, socioeconomics, pandemics, popular movies, climate change, and the genome.
"I was a Porky's kid, born in the southern hemisphere, I ate well, was raised in good home, I had access to education, and it was back when climate change was still deniable. Most people did not know what a pandemic was. I'm genetically predisposed to hair loss."
"Ma'am, you are, what we call, a Jaguar-5-hypercrab-superbear, and I'm going to have to ask you to go with the nice officer now."