ABSTRACT

Women who bear twins may possess a robust phenotype compared to non-twinning mothers. We examine mortality patterns for the singleton offspring of mothers of twins compared to the offspring of non-twinning mothers to determine whether they share the hypothesized robust phenotype of their mothers. Using data from the Utah Population Database, we show that both male and female singleton offspring of twinning mothers experience a survival disadvantage prior to age 5, no survival benefit or penalty between ages 5 and 49, and—for males only—a statistically significant survival advantage after age 50. We further examine the survival effects on singletons born before and after a twinset. We observe a survival disadvantage in early life for singleton offspring of twinning mothers born after the twinset for both sexes. In addition, we find a significant survival advantage at older ages in certain categories of male singleton offspring—a likely reflection of mortality selection. The findings suggest that while bearing twins may reflect a robust maternal phenotype, the toll of bearing twins may disadvantage subsequent offspring, especially during infancy.

摘要

与没有双胞胎的母亲相比，有双胞胎的女性可能具有强大的表型。我们检查了双胞胎母亲的单胎后代与非双胞胎母亲的后代的死亡率模式，以确定他们是否具有假设的母亲稳健表型。使用来自犹他州人口数据库的数据，我们显示，双胞胎母亲的单身男女后代在5岁之前都经历了生存劣势，在5至49岁之间没有生存优势或惩罚，并且-仅对于男性而言，统计学上显着的生存50岁后的优势。我们进一步研究对双胞胎出生前后单身人士的生存影响。我们发现生存不利在双胞胎母亲出生后的双胞胎母亲的单胎后代中，男女两性。此外，我们发现某些类别的单身男性后代在老年时具有显着的生存优势-这可能是死亡率选择的反映。研究结果表明，虽然双胞胎可能反映出强大的母体表型，但双胞胎的死亡率可能会对随后的后代不利，特别是在婴儿期。