This is the genetics: 4 v9 Z8 b, b% n! a0 o3 p6 z, a. W1 _* X4 h* `1 a+ U$ N
XY(man) x XX(woman) = 7 B7 t2 y( ~( g3 x, r* DXX or XY, XX or XX, XY or XY. Some people have a twin. 0 q& X) r' N% x1 G1 J9 ^& t* [! w& r1 J$ ^* d
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.) S+ y+ l: n7 P+ \# D# d& L- j
+ q8 F v5 f M1 a' [# yBecareful, eating drug may cause mutation although the possibility is not so high.