José A López-López, Kate Tilling, Rebecca M Pearson, Mina S Fazel, Elizabeth Washbrook, Yiwen Zhu, Brooke J Smith, Erin C Dunn, Andrew D A C Smith
Depressive symptoms in adolescence and adult educational and employment outcomes: a structured life course analysis
Psychological medicine
fraternalbirth order effect fboe research claim states older brother increases odds homosexual orientation men via immunoreactivity process known maternal immune hypothesis importantly older sisters supposedly either affect odds affect lesser extent consequently fraternal birthorder effect predicts association number older brothers homosexual orientation men greater magnitude association number older sisters homosexual orientation difference magnitude represents main theoretical estimand fboe addition comparable effects observable among homosexual vs heterosexual women triangulate empirical foundations fboe three distinct informative perspectives complementing first drawing basic probability calculus deduce mathematically body statistical evidence used make inferences main theoretical estimand fboe rests incorrect statistical reasoning particular show throughout literature researchers ascribe false assumptions effects family size adjusted could achieved use ratio variables second using datasimulation approach demonstrate using currently recommended statistical practices researchers bound frequently draw incorrect conclusions third reexamine empirical evidence fraternal birthorder effect men women using novel specificationcurve multiverse approach metaanalysis 64 male 17 female samples n 2778998 analyzed correctly specific association number older brothers homosexual orientation small heterogenous magnitude apparently specific men addition existing research evidence seems exaggerated smallstudy effects