Oligospermia
"I tried Clomiphene to increase my low testosterone without negatively affecting sperm quality. Unfortunately, just after my second dose (25mg) I woke up at night with numbness and tingling spreading over my whole left body side, with light tingling and muscle fasciculations continuing for over a week after disconinuing the medication. This is supposedly a very rare, but known, side effect of clomiphene, and was repeatable after trying it again after a few weeks. It also seemed to cause anxiety and even minor suicidal thoughts. On the plus side, it did probably increase my physical energy levels."