How can my wife conceive a baby boy?

Your wife...: ...Does not conceive a baby. The two of you do it together. The chance that you will conceive a boy is exactly 50:50 every single time, and there is nothing known that will reliably alter those odds.

Nothing specific: It is the swimmer(sperm) who gets there first that determines the sex of the baby. There is no special position, tea, day of the month or whatever else you heard that makes any difference.There are a lot of myths out there about gender selection; all work half the time.