Child spacing and birth order: effect on intellectual ability in two-child families

See allHide authors and affiliations

Science  01 Dec 1978:
Vol. 202, Issue 4371, pp. 995-996
DOI: 10.1126/science.568823


The effect on intellectual ability of the spacing of the birth of siblings was studied in two series of young men from two-child families: (i) 535 pairs of brothers and (ii) 1511 unrelated firstborn and secondborn. Birth-order effect and level of ability were not influenced by length of interval between firstborn and secondborn.

Stay Connected to Science