SHBG and obesity due to melanocortin 4 receptor deficiency: SHBG levels in low birth-weight boys were not statistically different from controls at age 2–3 months [41], but by age 8 years were lower in low birth weight girls [3], and low SHBG was found with obesity in both sexes by age 6–9 years [42] suggesting that the link between low SHBG and obesity is acquired at a young age.