“Correlation Between Oral Sex and a Low Incidence of Preeclampsia: A Role for Soluble HLA in Seminal Fluid?” C.A. Koelman, A.B. Coumans, H.W. Nijman, I.I. Doxiadis, G.A. Dekker, and F.H. Claas, Journal of Reproductive Immunology, vol. 46, no. 2, March 2000, pp. 155–66 (http://dx.doi.org/10.1016/S0165-0378(99)00062-5).
(Thanks to Paolo Usai and Eugene Rubach for bringing this to our attention.)
The authors, who are at Leiden University Medical Centre, The Netherlands, report that:
Forty-one consecutive primiparous women with a history of proteinuric preeclampsia and a consecutive control group of 44 primiparous women were asked if they practised oral sex (oral ejaculation) with their partner before the index pregnancy. If the answer was positive, they were asked if they were swallowing the ejaculate or not…. Our preliminary data show slightly lower levels of sHLA [soluble human leukocyte antigen] in seminal plasma in the preeclampsia group, although not significantly different from the control groups. An extension of the study is necessary to verify this hypothesis.
(That’s an except from the article “Boys Will Be Boys,” Published in AIR 15:3.)