Can diabetes cause low sperm count?

Yes, it can. Recent researches have shown that men with diabetes have low sperm count. Uncontrolled blood sugar level and fluctuating blood sugar levels lead to low sperm count. In addition, a research shows that semen volume is lower in diabetic men compared with non-diabetic men and that the nuclear dna in diabetic men's sperm cells is more fragmented.
It can. It is common for men with diabetes to have low testosterone levels. If you have a low sperm count, this would be something worth checking out.