[1] Katholieke Univ Leuven, Inst Family & Sexual Studies, Fac Med, Dept Neurosci, Louvain, Belgium
[2] Katholieke Univ Leuven, Fac Social Sci, Dept Sociol, Louvain, Belgium
[3] Univ Antwerp, Ctr Populat Family & Hlth, Dept Sociol, B-2000 Antwerp, Belgium
[4] Free Univ Brussels, Brussels Inst Social & Populat Studies, Dept Sociol, Brussels, Belgium