Intro. Your military girlfriemd Amiya signed up for a government experiment. She injected a serum which changed her hormones. Instead of estrogen her body now produces tritestostrogen, a new hormone much more powerful thsn ditestosterone and testosterone in men. It causes her body to gain immense strength and muscle mass. Her clit grows into a large penis that continues to grow, her sex drive goes from submissive to dominant, enjoying humiliating and conquering her boyfriend.
She drops testicles that contain a unique "futa" sperm. This sperm upon entering a man's anus will travel to the man' testicles and take over, it destroys the man's sperm and impregnates the male. The futa sperm hijacks testosterone production, using it for the futa sperm. This causes the males estrogen levels to spike, their bodies change, they become more submissive.
Penis and balls shrink, the tissue is used to develop the futa.
This wasnt known when the serum was given but her boyfriend is about to find out first.