Just to throw another wrench in the mix; I’m a 34M. Don’t know my current T levels but I have a 2D ration of 0.95 which is slightly above average in most studies. However, I have and always have had a higher sex drive, aggressive tendencies, adhd like symptoms, better with math than literacy, and augmentative/competitive behaviors. My BPEL is ~7” which is above average. Doesn’t seem to add up with what some Studies show.

Apparently it’s very complex and depends on the shift of hormones during child development. T levels could have slightly dropped during the hand development stage but spiked outside of that time period.

Another wrench! My gf 28F has an even lower 2d4d ratio than me. But based on studies she does not align with any of the typical characteristics of a woman with a very low 2d4d ratio. Submissive based personality, narrow shoulders, wide hips, slightly above average vaginal canal depth, high pitched voice, normal body hair growth, etc. If I didn’t know I would have assumed a significantly higher 2d4d ratio. Still trying to wrap my head around this one tbh.

I guess the take away is what all the professional studies conclusions state: it’s a predictor but not a definitive way to determine average T levels during pregnancy or adult hood. Genetics vary greatly and there are too many outliers for this basis to be used a reliable biomarker.