Data NInputvars=18
 Missing=-1.00		           
 Rectangular File=iqnl.rec
 Labels famid zygos 
  age_t1 sex_t1 var1_t1 var2_t1 var3_t1 var4_t1 var5_t1 var6_t1
  age_t2 sex_t2 var1_t2 var2_t2 var3_t2 var4_t2 var5_t2 var6_t2
 Select if zygos > 2 ;	!select dz's
 Select 
  var1_t1 var2_t1 var3_t1 var4_t1 var5_t1 var6_t1
  var1_t2 var2_t2 var3_t2 var4_t2 var5_t2 var6_t2 ;