Does supplementation with zinc improve sperm health or fertility?

Animal studies show that zinc deficiency is associated with low testosterone, abnormal testicular function, and infertility.^[1][2][3][4] Some human studies have reported similar observations,^[4][5][6][7] but because of the lack of clinical trials, conclusions about the effect of zinc supplementation on sperm health or fertility aren’t currently possible.^{[8][9][7][10]}