What is the main difference between sperms and eggs of humans? Write the importance of this difference.

(N/A) The primary difference is that sperms are motile,while eggs are non-motile.
The importance of this difference is that the motility of the sperm allows it to travel through the female reproductive tract to reach the egg for fertilization.
Alternatively,another significant difference is in their chromosomal content:
Sperms contain either an $X$ or a $Y$ chromosome.
Eggs contain only an $X$ chromosome.
The importance of this difference is that it determines the sex of the offspring upon fertilization:
If an $X$-bearing sperm fertilizes the egg,the zygote becomes $XX$ (female).
If a $Y$-bearing sperm fertilizes the egg,the zygote becomes $XY$ (male).