"High levels of dopamine can powerfully rewire the brain and alter sexual tastes....Similarly, continued porn use can’t change your sexual orientation, but it can change what type of porn excites you. Desensitized porn users (low dopamine signalling) search for whatever will jack up their flagging dopamine. Once they find it, dopamine spikes, and the process of re-conditioning their sexual response has begun. If they keep masturbating to the new genre, subtle brain changes rewire their sexual circuits, leading to an inadvertent, and often alarming, change in porn tastes that make it difficult, or even impossible, to climax to earlier tastes." (Your Brain on Porn)