Testosterone and estrogen are steroid hormones that bind cell surface receptors, enter the nucleus, and control gene expression.

“testosterone and estrogen are both steroid hormones one of the reasons those are interesting is that because of their structure they're able to bind cell surface receptors and have effects on those cells they are also able to pass through okay the hormones okay here I'm not talking about bpas and bps's but the hormones testosterone estrogen can actually get to the nucleus of cells and can control gene expression”

“As I said, the testosterone or other steroid hormones, estrogen as well, bind to receptors. And those receptors turn on genes.”