December 2022 in “The Aging Male” Lower 2D:4D ratio and older age increase the risk of severe hair loss in men.
22 citations
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May 1986 in “Clinics in endocrinology and metabolism” Certain finger length ratios and body hair patterns may predict side effects from birth control pills in women.
Digit ratio likely doesn't predict male hair loss.
4 citations
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August 2017 in “Journal of Cosmetic Dermatology” Finger length ratio may indicate male hair loss.
December 2025 in “Anatomy (International Journal of Experimental and Clinical Anatomy)” Palmaris longus muscle absence is uncommon and not linked to gender, hand side, or finger ratio.