Most male infertility issues are diagnosed via semen analysis, which includes a number of parameters, with three that are of primary importance: sperm count, motility (the percentage of sperm that are able to swim), and morphology (the percentage of sperm that are normally-shaped).
However, results can vary tremendously between samples anaylzed (i.e. two samples from the same man could show very different results) and different laboratories interpret results differently, too. For this reason, urologists disagree about the reliabilty of the test and its ability to guide treatment decisions.
The reality is, male infertility can't be reduced to a single semen analysis category. For instance, if a man has a low percentage of sperm that are normally shaped but a high sperm count, he can likely conceive naturally. As you can see below, many men who fall below "normal" ranges — sperm count below 40 million, motility under 40%, or morphology of less than 5% — do go on to father children naturally.
There are a number of circumstances that cause male factor infertility, varicocele being the most prevalent. Varicocele, a vein abnormality in the scrotum that can lead to decreased sperm production, is found in 30% of men with MFI, though is not necessarily the cause. Surgically repairing the varicocele works best when the patient meets these criteria:
While research is divided on how helpful varicocele surgery is in resolving MFI, it certainly delivers better outcomes when coupled with IUI compared with doing IUI alone. The data comparing varicocele surgery versus IVF is sparse to non-existent.
Azoospermia is a condition where the male produces no sperm and it is simply impossible for him to conceive naturally. In many circumstances, azoospermia can be treated if the underlying condition involves a hormone imbalance or blockage. When those aren't what's causing the azoospermia, things get harder. An invasive procedure called MicroTese is often performed to find sperm within the testicle and, when sperm is found, IVF with ICSI is deployed. The birth rates resulting from this technique hover between 20 - 30%.
In 10% of male factor patients, the issue is caused by a hormone deficiency. This can typically be addressed through hormone therapy. Most problematic are the number of men who take testosterone to increase their vitality. This dampens their natural ability to produce testosterone and creates significant fertility challenges.
A man's lifestyle can greatly impact his level of fertility. Smoking is a major culprit, whereas weight gain, caffeine and alcohol likely have a "threshold effect," and only become problematic beyond a certain level.
Exercise is a double-edged sword when it comes to male fertility. Moderate levels of excerise are associated with improved semen perameters, but intense and sustained levels of exercise can become problematic.
As men get older, it becomes gradually harder for them to conceive, and children born to men who conceived at 50 or beyond have a 2 - 3% higher risk of schizophrenia, autism or other neurological and developmental challenges.