Toronto Public Health is issuing instructions for men after researchers in the United States suggested condom misuse is an epidemic.
Richard Crosby with the Kinsey Institute condom use research team, says men underestimate how complicated they can be.
He says men often do not wear condoms throughout sex and do not put them on right.
Crosby was the lead editor for a special issue of the journal Sexual Health.
He says condoms are the best vaccine for small pox, SARS, cholera and other infectious diseases.