Shettles method?

So my friends mom was an OB nurse for 22 years and told me about this last night, she said she was about 90% accurate in predicting the sex with her patients this way, just for fun! She also said she planned her 3 girls this way.. and it made me quite curious to see if it was accurate for some/most?

According to Shettles: if you conceive before cycle day 14 then it will be a girl and if you conceive after cycle day 14 it will be a boy. The science behind that is girl sperm are slower but live longer so having sex before you ovulate, the boy sperm get there first but die off waiting for the egg and the only sperm left to fertilize the egg when it comes are the girl sperm.

I went back and tracked my first son and I conceived on CD 19 so this was accurate for me. This time we conceived on cycle day 9 so we will see.

Was this accurate for anyone? 😊