I'm restless

Hello frns I'm 16 weeks prego n I'm so anxious to know my baby gender.. Im already having a girl child n my inlaws wants a boy child dis time day by day I'm getting anxious n nervous... What if I have baby girl again.. I don't have brothers I know how tough it is olin d society.. many countries don't have that feeling but here in India boy is a must for a family to extend their generation n here it's illegal to know d gender.. so how to know if I'm carrying a boy or not as I'm gaining weight I have a fear dat it myt b a girl coz ppl usually say if v r carrying girl child we gain more weight than boy child.