This is the genetics: : u+ w* N& f2 m; \ Y3 [- H; F' f2 xXY(man) x XX(woman) = . n+ }3 g" C5 s2 [! F+ i" J
XX or XY, XX or XX, XY or XY. Some people have a twin. , w( S4 ~6 Z7 U0 o g9 [" H& u+ o6 R! S5 S( @
If you really need a boy, you can ask a doctor to take your Y only and injiect into your wife's XX, then you will have boy only.8 _" r2 O+ v+ P- E* e* ~# s& J
* R8 V0 ^( e( E$ }3 CBecareful, eating drug may cause mutation although the possibility is not so high.