This is the genetics: % R9 K1 _6 M# C, n! \0 ?" T; [4 ?! w; k% a# V
XY(man) x XX(woman) = $ u1 o9 s. r/ Y$ C N: q6 c
XX or XY, XX or XX, XY or XY. Some people have a twin. , l* s7 O' n- P6 F7 r ' p& N3 I$ N8 L9 c% |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.2 M Z ]# c! o. i
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Becareful, eating drug may cause mutation although the possibility is not so high.