A British survey of 3,000 people has discovered that 13 percent of men had unprotected sex with more than one person during the past five years, compared with 7 percent of women.
According to the Lloyds Pharmacy study, men who took a chlamydia test were twice as likely to have the infection as women.
The study's figures revealed that 13 percent of men who bought chlamydia tests from its online doctor service tested positive for chlamydia compared with just 6 percent.
Clare Kerr, head of sexual health, said the findings raised concerns that men were delaying tests until they had symptoms, reports The Daily Express.
She added: "This is particularly worrying as many STIs don't have obvious symptoms, so men could be putting themselves and their partners at risks by delaying tests."