Chewing tobacco also may cause low sperm counts .

咀嚼烟草同样可以引起精子数目减少。

Just need some sperm sample .

采集点儿精液样本罢了。

The irony is that sperm whales can thank oil for their species 's survival .

颇具讽刺意味的是，抹香鲸应该感谢石油拯救了它们的种族。

Once boys hit puberty , their sperm cells divide every 16 days .

男孩儿们到了青春期后，精细胞每16天分裂一次。

A microscope image of ivd sperm .

显微镜下的试管培育精子。