What is normal morphology and how does it help with improving fertility rates?
A sperm should have a Head which contains the nucleus which harbors the DNA. The head is followed by a neck, a mid-piece and a tail. One would think that most sperms should appear normal under the microscope. However, this is hardly the case. Even in a normal fertile male the majority of sperm appear abnormal. So what criteria are we using to certify this?
Well, there are two criteria, one used by Kruger and the other is the WHO criteria. The Kruger criteria are very strict in defining what an abnormal sperm is. So how does fertility play out with abnormal sperms? It is not necessary that only a normal sperm should fertilize the egg. Even abnormal sperms can. However, the fertility rates are supposed to be lower as abnormal sperms can be associated with other abnormalities like low sperm count and motility.
There is no evidence to show that if one possesses more abnormal sperms then the children born are to be abnormal. There is only a chance that these children also may have abnormal sperms.
Unless sperm morphology is disrupted by an identifiable cause, it is very difficult to correct it. There is no clear relation between smoking/alcohol and sperm morphology. Infections are sometimes blamed for the same.
Do not read too much into the morphology as it is a very subjective finding according to me. The person looking through the microscope decides what is abnormal and what is not. Even then, an abnormal sperm can fertilize.