Jiaxuan,
It's not true for me. My elder girl didn't crawl at all. My younger child is a boy. I used the method (forgot the name) which is a hypothesis by a doctor. He says that boy sperms die faster and swim faster, so if you want a boy, do not try when u test positive for ovulation (for clearblue kits) because u will only ovulate 24 to 48 hrs later once u tested positive (assuming u have been testing days before). Try abt 1 to 2 days after having tested positive.
In addtion, i also used the calender which predicts gender (note that age and month must be read in chinese methods, e.g our chinese age is a year older, and we must read only lunar months).
Of course, I also used preseed. There are some sites that says a acidic womb environment can conceive girls. preseed helps to give a ph balance womb environment.
Oh, i was very hardworking in using basal thermometer to take daily temperature to predict my ovulation, and this complemented the use of ovulation sticks, in the sense that i will less likely start using the clearblue sticks too early. There are only 5 sticks in each box and it is expensive haha.
Hope the above helps.
Cheers!