Exhibits · Chapter 2 · Impermissible and Unavoidable in Equal Measure
Exhibit 08: The Fork: One Surge, Two Chemistries
One testosterone surge forking in two. Down one path an enzyme makes DHT and builds the body; down the other, aromatase makes estradiol and wires the brain.
A single testosterone surge from the testis forks. 5-alpha-reductase, from the gene SRD5A2, converts it to DHT, which drives the outward body build. Aromatase, from the gene CYP19A1, converts the same testosterone to estradiol inside the neuron, which wires the brain.