Male infertility

How to define male infertility? What are the symptoms of this disease?

Существует множество различных факторов, определяющих мужское бесплодие. Иногда совершенно здоровый внешне мужчина совершенно не способен зачать ребенка.

Thanks so much for sharing these. I have read a lot of articles with similar topics but none of them are as detailed. I will learn more and practice  5 letter words