Sir mine are twin babies ,thier birth weight is 2.200 each ,now they are 13months old,twin boy 10.500gms and twin girl 8.200, I give diet to them equally and every month I check their weight,baby boy increases weight 500-600 every month,but baby girl not increasing weight hardly she gains weight 50-100gms every month,what should I do ,plzz suggest me to increase her weight