Health Canada is again warning Canadians of the potential danger of using donated semen for assisted conception from questionable sources, specifically off the Internet.

Donations procured through unreliable means like ordering off the Internet may not be safe due to the possibility they have not been properly screened and tested, the agency said.

Untested semen could pass on HIV/AIDS, Syphilis, Gonorrhea, Chlamydia and Hepatitis B and C to mothers and unborn children, it warned.

This second warning, following one issued in December 2010, comes in "light of media reports involving the advertisement of  'fresh' donor semen over the Internet, and websites advertising such services," the release said.

It further warned that this semen has not been processed and cryopreserved [frozen] and very well might not have been tested.

There are regulations for acquiring semen for assisted conception. Distribution of "fresh" semen is prohibited in Canada. Donors are required to be screened and tested before donating and six months after donating. The semen is quarantined for a minimum of six months in order to lessen the risk of passing on any infectious disease.

A list of semen processors and importers are kept by Health Canada and are subject to regular inspections.

Health Canada adds that Canadians considering using donor semen should always consult with health care professionals.