Re: What is the size comparison between a human male sperm and a human ovum?

The normal human sperm head has a width range of 2.5 to 3.5 microns 
(micrometers) and a length range of 5 to 7 microns.  The normal semen sample 
will only have between 14 to 20 percent normal sperm.  This includes not only 
the appropriate head size range but must also have the normal smooth oval shape 
with the right size acrosomal cap on the top of the head.  The normal cilium is 
about 80 microns long.  From this you can see that the human sperm head is in 
the same size range as the red blood cell but of course it doesn’t have the 
biconcave shape of the RBC.  When we come to the ovum or egg the size is one of 
the largest in the body except for the conducting cells of nerve and muscle.  Of 
course muscle fibers (cells) are large because they are multinuclear as a result 
of fusion of many individual cells into a syncytium.  Nerve cells are large as a 
result of their processes (axons) but the cell body (soma) is not nearly as 
large as the egg.  The immature egg, before it is stimulated by follicle 
stimulating hormone (FSH), is about 60 microns in diameter.  Once the follicle, 
and thus the egg inside, is stimulated to ovulate the ovum will begin to mature 
as the follicle matures and the egg will reach a final diameter of about 120 to 
150 microns.  We used to do a test in my andrology laboratory at the Jones 
Institute for Women’s Health called the hemizona assay.  It is now done in a 
different lab that specializes in only that one test.  In a really good donor 
semen sample over 150 sperm would bind to one hemizona.  This is just half of 
the zona pellucida so you would want to multiply that by 2 to get the total 
number of sperm heads binding to this “shell” of the egg in a healthy 
individual.
 Hope this helps
 Dr. Swanson