Sperm cells are either X or Y. The Egg cell is always X. If X-Sperm cell meets the egg(X) the baby will be a Girl (XX). If Y-Sperm cell meets the egg(X), the baby will be a Boy (XY). The Y-Sperm cells move fast but die fast (its lifespan is about 24hrs). X-Sperm cells move slowly but survive longer (up to 3-4days).

Therefore, if you have intercourse some days before ovulation, most of the Y-Sperm cells would have died leaving mostly X-Sperm cells to fertilized the egg

Here's a simple way to calculate your ovulation period.

1. From the first day you see the blood of your period.
2. Pick up a calendar and count 15 days including the first day of the blood stain.
3. Mark the 15th day with a pen.
4. Mark 3 days before the 15th day, and mark 3 days after the 15th day.
6. You will notice you have 7 days marked.
These 7 days are your ovulation/fertile days also known as unsafe period.
That is if you have sex on any of these days, then you have 98% chances of being pregnant.
7. Do this every month diligently
For Example
1. If your period is 11th July, ,
2. 15 days after the first day of the blood stain will be on... https://allsinglesandmarried..com/2019/12/steps-on-how-to-select-your-babys-gender.html?m=1