Height at ages 17–20 by preceding and subsequent birth intervals, Swedish men born in 1962–1979. The analysis population for examining preceding birth intervals consists of individuals in sibling groups with at least three children, excluding the firstborn. The analysis population for examining subsequent birth intervals consists of individuals in sibling groups with at least three male children, excluding the last-born. The reference category is a birth interval of 25–30 months. Error bars are 95 % confidence intervals