See how important it is to be FAMALE GENDER...EVEN God  has made female so special that  ONE EGG IS SO PRECIOUS THAT billions of Sperms fight for it.. Jokes apart ....female has limited. Reservoir  so mature is that way one egg at.a time ..and Sperm has to come from  other body ..need to travel all the way from vagina to ovary...given all circumstances in all odd situations at least few would be able to reach... Must say Good question

Because sperms have to reach the egg. Many try and only one is able to reach. Egg doesn't have to go anywhere.

It's a nice question .... The answer will be that the egg is already in our body an in a suitable environment to concieve whereas sperms has to travel throught the same tract as of the the male urination tract and it has to see the outer environment and then vaginal tissues which is a foreign place for sperms and travel all the way from cervix by pass the white discharge and go up to uterus and tubess and then meet the egg..... There is so much wastage which happens during the process to reach a egg... Hence nature had created it.... But ultimately only one sperm is allowed to enter the egg....