What should be the ideal timing for sex -the ovulation day or previous, to conceive a baby boy naturally.can a hormone vaccine help?

None short of lab: There are several "methods"proposed by a variety of sources that include timing or rituals but none work.There is no vaccine or shot that helps. If you want to spend big at a fertility center they can test & select a male embryo for implantation. This has no guarantee of success.

No.: Sex selection is not a good idea, in general, as it can lead to societal upheavals and imbalances. In short, there is no simple way to preferentially conceive a boy or girl. The only method that works for sure is preimplantation genetic diagnosis with in vitro fertilization - both of which carry significant risks and large expenses. Take Folic Acid 1-5 mg and have faith in god would be my advice.