I will give you just a brief response as I'm sure some of our male members will pop in to respond to your question.
It is not so much the disease (Lupus) that my interfere with male fertility as it is some of the medications that male Lupus sufferers may have to take.
Researchers have found sperm damage linked to infertility is common in men with lupus and that this damage appears to be related to a commonly used treatment for the disease. Intravenous cyclophosphamide (also known as Cytoxan) used in high doses for a prolonged period of time was found to be the constant in a study of men with Lupus and infertility. The results of the studies showed that men with lupus who had used this drug for a prolonged period or in high doses, had lower average sperm counts and sperm motility. They also had a lower sperm volume and a lower percentage of normally formed sperm.
I hope that this bit of information is helpful to you. Hopefully, someone else will provide additional information.
Peace and Blessings
Look For The Good and Praise It!