IGHG3 and Reduced sperm motility: Chlamydia trachomatis Pgp3 IgG1 and IgG3 antibodies were associated with impaired sperm motility (asthenozoospermia) (18.6% vs 6.3%, P = .006 for Pgp3 IgG1; and 21.4% vs 8.0%, P = .03 for Pgp3 IgG3).