Digit ratio (2D:4D) as an indicator of body size, testosterone concentration and number of children in human males.
OBJECTIVE
The 2nd to 4th digit ratio (2D:4D) is thought to reflect exposure to androgens during foetal development. This study examined the relationship between low (more masculine) and high (more feminine) 2D:4D and body size at different stages of the life course, adult testosterone levels and number of children among males.


METHODS
Five hundred and fifty-eight men from rural Poland at the Mogielica Human Ecology Study Site participated in this study. Life history data and anthropometric measurements were collected. Salivary morning and evening testosterone levels among 110 men from the same population were measured.


RESULTS
Low 2D:4D was related to higher birth weight (p = 0.04), higher birth length (p = 0.01), higher body mass during childhood and adolescence (p = 0.01), higher BMI (borderline significance, p = 0.06), higher number of children among fathers (p = 0.04) and higher testosterone levels during adulthood (p = 0.04).


CONCLUSIONS
This study shows, for the first time in a single population, that digit ratio is related to sub-adult body size at different stages of the life course, adult testosterone levels and number of children. The observed results suggest that digit ratio might be a valuable predictor of male body size and reproductive characteristics.
Department of Environmental Health, Faculty of Health Sciences, Jagiellonian University Medical College , Krakow , Poland .
Magdalena
M
Klimek
Andrzej
A
Galbarczyk
Ilona
I
Nenko
Louis Calistro
LC
Alvarado
Grazyna
G
Jasienska
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry; D049628:Body Size; D002648:Child; D002675:Child, Preschool; D005191:Family Characteristics; D005385:Fingers / Q000033:anatomy & histology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011044:Poland; D012959:Socioeconomic Factors; D013739:Testosterone / Q000032:analysis*; D055815:Young Adult
D013739:Testosterone
2D:4D; body size; number of children; rural population; testosterone