The influence of variation in parental height dimorphism on same-sex parent-offspring height differences

This study evaluates how adjusting for parental height dimorphism influences height differences among parents and same-sex offspring distinguished by parents' early backgrounds.

Regression analyses using data from independent groups of Taiwanese families, 56 with sons and 51 with daughters, evaluate how adjusting for parental height dimorphism influences same-sex parent-offspring height differences among families grouped by grandfathers' occupations into three status categories reflecting good to relatively poor early parental environments.

Parental height dimorphism was statistically significantly associated with same-sex parent-offspring height differences (father-son: mean Δ = 3.88 cm, β = -71.47 ± 11.49 SE, t = -6.22, p ≤ .0005; mother-daughter: mean Δ = 4.15 cm, β = 80.46 ± 18.52 SE, t = 4.35, p ≤ .0005). Adjusted mean father-son differences increased significantly across grandfathers' occupation categories (Privileged, Δ = 0.60, Business, Δ = 4.06, Farming & Labor, Δ = 5.28; p = .011). Mother-daughter differences were substantial, from 3.33 cm to 5.06 cm, but did not differ significantly across occupational categories (p = .63).

Adjustments here for variation in parent height dimorphism did not alter original interpretations that while female growth may be more canalized, it is similarly capable of responding to improvements in developmental contexts. Patterns of same-sex parent-offspring height differences across grandfathers' occupational categories remain best accounted for by Taiwan's rapidly expanding economy, substantial income equity and reductions in biases favoring sons over daughters. Adjustment for sub-group variation in parental height dimorphism should be considered in similar studies in the future.