Model summary R R² Adjusted R²     Standardized error of the estimate All children 0.556 0.309 0.284 2.99 All boys 0.595 0.354 0.311 2.99 Unstandardized coefficients Standardized coefficients Significance Collinearity statistic (tolerance) Beta Standard error Beta   (N=495)  (N=266) Constant   44.73 3.960 <0.001 <0.001 Examiner (A /B)   -2.776   0.336   -0.392 <0.001 <0.001 0.732 Date of examination 0.001 0.001    0.092 0.030 ---* 0.927 Interval of examination to last meal (min) 0.006 0.003    0.087 0.063 0.136 0.755 Stability of states (no / yes) 3.063 0.500    0.256 <0.001 <0.001 0.944 Time between rupture of membranes and birth (min) -0.027 0.019   -0.060 0.153 0.241 0.955 Apgar score at 5 minutes 0.691 0.327    0.089 0.035 0.033 0.938 Neonatal illness (no / yes) 0.486 0.364    0.056 0.182 0.113 0.940 Level of higher one of parents´ profession or occupation (low / high) -0.902 0.308   -0.128 0.004 0.003 0.873 Mother´s age (years) 0.067 0.032    0.098 0.035 0.010 0.770 Maternal weight (kg) -0.031 0.015   -0.091 0.032 ---* 0.913 Weight gain during pregnancy (kg) -0.044 0.031   -0.062 0.148 ---* 0.918 Early abortions   (no / yes) -0.676 0.342   -0.082 0.049 0.010 0.959 Other non- obstetrical disease of mother (no/yes) 1.178 0.651    0.076 0.071 0.177 0.931 Log10 of PCB 156 4.370 1.758    0.386 0.013 0.048 0.069 Log10 of PCB 180 -5.168 1.757   -0.460 0.003 0.028 0.067 Log10 of b- HCH^&    --- ---       --- --- 0.008 --- Log10 of musk xylene^&    --- ---       --- --- 0.032 --- + * : Not in model for boys & : Not in model for all children