I have read this from friends and is mostly around in subcontinent that in order to get healthier babies (with no defects and good health), one should avoid ejaculation for a couple of days before trying for pregnancy.
Is this true?
You mentioned in your comment that the sperm is healthier. If anything, ejaculation prior to sex will get rid of the old sperm and give the newer, healthier sperm more of a chance.
Anyways, the health of a sperm cell really doesn't matter. First thing, all the sperm does is transfer the DNA to the egg, nothing else. DNA doesn't change for a single cell over time. Atleast, not with any significant probability--mutations are possible but rare--if there was a mutation it is far more likely to have come from a faulty meiosis than 'aging' of a sperm.
The only difference that waiting does make is that it increases the chance of conception.