Critical Day for gender?

Has the critical days been correct for anyone on gender based off the biorhythm chart?

Biorhythms were invented by a mental patient over 100 years ago before they even really knew what ovulation was, based on the idea that "all women have 28 day cycles" which they don't. They have been debunked in at least 134 different studies. I do not recommend worrying about biorhythms as a part of swaying.