For what it's worth...
I am not a scientist, but I think it is true that it is the man who decides the sex of the child (providing the X or Y chromosome which decides such things).
My husband has a theory that whether or not you have boys or girls is determined by the nature of the man. A man who is not as determined will tend to have girls but one who is very determined will tend to father sons. But the balance between husband and wife also comes in as a factor. If the wife is the person who makes the decisions then she is the stronger.
My husband is a hard man, very strong and determined. We had two boys, then my husband decided to work on himself because he wanted a girl. After some pretty hard work on himself, along came our girl.
Anyway I pray that you can accept the will of God joyfully and shun those negatives.
I had never heard of that.
There's a reason you haven't heard of that -- it's an old wives tale proven by 1 or two cases of anecdotal evidence AT BEST. At worst, it's nothing but a steaming load.
If this were true, we'd have 6 boys instead of 1 boy and 5 girls.