How can i have a son?

My husband and i have 2 daughters that we love dearly and wouldn't trade for the world but we so desperately want a little boy i know it would make him so happy to have a son to carry on his name plus he comes from a family of mostly boys and i know the of the baby depends on him but im convinced my side has a curse my mom and dad have 4 daughters and 6 granddaughters there isn't a boy at all any advise would be helpful