Biological samples, including cryopreserved sperm, are routinely X-rayed during air shipment. The goal was to investigate the impact of X-irradiation used for checked and carry-on luggage on bovine sperm chromatin integrity and postfertilization in vitro embryonic development.
From the Introduction:
"Air transportation of biological material such as sperm, ova, and embryos has become common with the advent of assisted reproductive technologies. These biological materials are exposed to X-irradiation at ports of entry and exit. It is not known whether the levels of X-irradiation employed at airport security checkpoints adversely affect bovine sperm chromatin or affect sperm potential fertilizing ability and embryo development rates...The goal of this study was to investigate whether exposure of frozen bovine sperm to X-rays generated by airport security X-ray machines for carry-on luggage and for checked luggage would induce changes in sperm chromatin and cause a reduction in rates of in vitro fertilization and embryo development."
From the Discussion:
"Multiple exposures (up to 3 doses) of frozen bovine spermatozoa to X-irradiation as a result of airport screening of checked luggage did not apparently damage sperm chromatin integrity as measured by SCSA. Although there were no significant differences in oocyte cleavage rates or development to blastocyst stage for any of the treatments, a possible detrimental trend for sperm exposed to 3 doses of checked luggage X-irradiation was noted."
The complete study is attached (PDF).