Titanium nanoparticles can affect male reproductive function, like sperm movement and quantity. Scientists gave mice a single injection of titanium nanoparticles and found that sperm movement decreased within a day and stayed low for up to 9 days at a lower dose. Surprisingly, sperm numbers didn't change in the testis or epididymis during the experiment, suggesting the nanoparticles might target mature sperm. When sperm was directly exposed to titanium nanoparticles, it also showed reduced movement, DNA synthesis, and energy levels. This study suggests titanium nanoparticles have both immediate (on mature sperm) and long-lasting (on the testis) effects on male reproductive function.