Coital frequency and twinning

Abstract

In a comparative study to enquire whether parents of twins, especially of dizygotic twins, have a higher frequency of sexual intercourse than parents of singleton infants, data on sociodemographic status, coital frequency and other variables were collected using a postal questionnaire. Parents of all twins born alive in Denmark in 1984 or 1985 were included as cases and a random sample of parents of singleton infants born in the same period were controls. No evidence of any difference in coital frequency was found between parents of twins (neither dizygotic twins nor monozygotic) and parents of singleton infants.

Social class and human twinning

“…Two hundred and fortythree twin pairs were classified as MZ, 382 as DZ and 202 pairs could not be classified from the questionnaire data. The sensitivity (test for likeness) of the method examined on children of similar age was 94%, and the specificity (test for unlikeness) was 100% (Bonnelykke, Olsen & Nielsen, 1990).…”

Coital Frequency and Twinning

“…So, although the data of Bonnelykke et al (1990) are impressive numerically, they do not constitute decisive evidence against the hypothesis.…”

Zygosity Diagnosis: When Physicians and DNA Disagree/Twin Research: Sex-Discordant Chimeric Twins; Unrelated Bone Marrow Transplantation in Infant Twins With Congenital Amegakaryotic Thrombocytopenia; Twin Study of Attractiveness to Mosquitoes; Twins Coping With Crisis/Media Highlights: The Less Favored Twin; Paternity Issues; Twins With Late-Onset Tay-Sachs Disease; Triplets at MIT

“…Of course, non-paternity rates vary considerably across populations and regions, from 2% in a representative Mormon sample to 30% in a southeastern British sample; the British data were based on blood group analyses from an unpublished study of residents living in one town (Olson, 2007). A link between a greater frequency of sexual activity and fraternal twinning has also been reported, based partly on an elevated frequency of illegitimately conceived fraternal twins (James, 1992); however, an earlier study did not find differences in coital frequency among parents of MZ twins, DZ twins, and singletons (Bonnelyke et al, 1990). The foregoing is generally consistent with higher rates of heteropaternal superfecundation than have been reported.…”