[1] Statens Serum Inst, Dept Epidemiol Res, Copenhagen S, Denmark
[2] Aalborg Univ, Ctr Sexol Res, Dept Clin Med, Aalborg, Denmark
[3] Yale Univ, Yale Hastings Program Eth & Hlth Policy, New Haven, CT USA
[4] Hastings Ctr, Garrison, NY USA
[5] Univ Oxford, Uehiro Ctr Pract Eth, Oxford, England
[6] Michigan State Univ, Coll Human Med, Dept Pediat & Human Dev, Marquette, MI USA