The effect of parental and maternal-fetal histocompatibility at MHC on sex ratio in offspring

P. Astolfi, M. Martinetti, F. Gigli-Berzolari, M. Cuccia

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The secondary sex ratio (male births of total births) variation was investigated as a function of MHC antigens. Previous studies have indicated that at conception male zygotes are more frequent than female ones and abortions of male fetuses prevail. The present investigation addresses the question whether the histocompatibility relationships either between parents or between mother and offsprings may favor or hinder the outcome of pregnancy: particular combinations may cause distortions in the sex ratio. The results of the analysis of a sample of fertile families, demonstrate that, in first parities, female births are favored when parents share antigens at both HLA-A and -B loci (S.R. = 0.389), and mothers and fetuses share antigens at the HLA-B locus (S.R. = 0.222). The lack of antigens shared by parents at the three loci HLA-A, -B and -DR increases first male births (S.R. = 0.696). In the case of fetal maternal histocompatibility at DR locus only a slight, non-significant, increase in male first births (S.R. = 0.667) was observed. The effect of histochompatibility at HLA-B locus alone requires further investigation in order to assess the possible selective effect against male histocompatible embryos.

Original languageEnglish
Pages (from-to)172-177
Number of pages6
JournalTissue Antigens
Issue number4
Publication statusPublished - 1990

ASJC Scopus subject areas

  • Immunology
  • Cell Biology


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