Many families first notice something is different when a baby with typical female anatomy doesn’t develop as expected at puberty, such as absent periods (primary amenorrhea) and minimal breast development despite normal growth. Doctors may then investigate with hormone tests and imaging, finding underdeveloped or absent ovaries and sometimes streak gonads, which leads to genetic testing that reveals 46,XX sex reversal 1; in some cases, clues appear earlier, like atypical genital development at birth or differences seen on prenatal ultrasound. If you’re wondering about the first signs of 46,XX sex reversal 1, they’re most often recognized in early adolescence when puberty doesn’t start or progress on time, prompting evaluation for how 46,XX sex reversal 1 is first noticed.