My left testis got hurted during a football match. I then found the left testis has become smaller and after masturbation the sperm is now less. Will I be able to make my partner pregnant in the future?
The reason God designed the male body with two testicles is so that you have a back up in case one is damaged. Even if one testicle is unable to produce sperm, you still produce sufficient sperm to get your wife pregnant. However, it is better not to need a backup. This is why a cup should be worn during sports.
A doctor should look at your testicle to make sure that the damage is not permanent. A fertility test can be done to make sure you are still producing sufficient sperm.
A damaged testicle will not impact the amount of semen you produce. The bulk of semen is produced by the seminal vesicles which are inside your body in the groin region. The testicles produce the sperm, but the amount of sperm in each ejaculation is less than a drop by volume. If your testicle stops producing sperm, you would not be able to tell from the volume that you ejaculate.