The Statistics Canada report, released Wednesday, shows 68 per cent of sexually active Canadians aged 15 to 24 reported using condoms in 2009-2010, compared to 62 per cent in 2003.
"I think it's great news that we're seeing more kids, young adults using condoms," said Sarah Flicker, an associate professor of environmental studies at Toronto's York University, who specializes in adolescent sexual and reproductive health.
"But it's a huge problem that almost three in 10 are not using protection when they're having sex," she said.
The agency's Canadian Community Health Survey for 2009-10 found that two-thirds of respondents aged 15 to 24 reported having had sexual intercourse at least once, a proportion that doesn't differ significantly from 2003.
While only 30 per cent of those aged 15 to 17 reported having had sex, the numbers rose to 68 per cent of 18- and 19-year-olds and 86 per cent of those aged 20 to 24.
Younger teens also were making forays into physical intimacy: in 2009-2010, nine per cent of 15- to 24-year-olds reported they first had sexual intercourse when they were under 15, and about 25 per cent had experienced intercourse for the first time at age 15 or 16. These results did not differ significantly from 2003.
"Sexually transmitted infections are highest among our youth and young adults, so the fact that we're seeing so many young people exploring their sexuality without using adequate protection is worrying," said Flicker, referring to the 32 per cent who reported not using condoms.
"So I see this as both good news and bad news."
The report also found that condom use appears to drop as a young person's age rises.
While 80 per cent of 15- to 18-year-olds reported using condoms, the figure dropped to 63 per cent among those 20 to 24.
Dr. Ashley Waddington, an obstetrician-gynecologist at Queen's University, suggests the decrease in use with age may relate to how condoms are viewed.
"I think in the younger age groups, they're more likely to depend on condoms for birth control, whereas the older age groups, once they're gone off to college, university, they may be living independently, they often seek out other forms of contraception," Waddington said from Kingston, Ont.
As younger Canadians move through their 20s, they tend to get involved in longer-term, more committed relationships and stop using condoms because they're monogamous and using other forms of birth control, she added.
Flicker said many young adults, as they get into more stable relationships, often don't see themselves at the same kind of risk for sexually transmitted infections, or STIs, as they might have at a younger age.
"Because I think a lot of young adults think about condoms as birth control rather than as an STI control," she said.
"One of the things we should be doing is teaching our kids and young adults that it's really important to think about using birth control and condoms. That's the best way to both prevent pregnancy and sexually transmitted infections to keep them safe.
"I think a lot of the time they're most worried about pregnancy and they forget about the life-threatening consequences of sexually transmitted infections like HIV or untreated syphilis, gonorrhea or chlamydia."
Waddington said that mind-set can be potentially dangerous because even if a couple is monogamous, one or both partners could conceivably have been infected during a previous sexual liaison or relationship and be unaware because they show no signs of disease.
"You could be with them for six months already, but they could be carrying something that they've had previously and be asymptomatic," said Waddington, who is doing a fellowship on contraception research and education.
Some STIs, such as genital herpes and human papillomavirus, or HPV, can persist and not create any outward symptoms for a long period of time, she said.
As well, rates of infection for gonorrhea and chlamydia have been rising steadily over the last two decades, particularly among the 15-to-24 age group and especially for females.
Waddington believes people may be engaging in slightly riskier sexual behaviour as HIV-AIDS has become less prominent in the public discourse, due in part to antiretroviral drugs allowing people to live much longer with the disease.
"I think that people paid attention to sexually transmitted infections when this deadly form of sexually transmitted infection was really prominent, and I think there's a lack of education or understanding about the effects of some of the 'lesser' STIs."
But even though chlamydia, for instance, is treatable, infection can still lead to pelvic inflammatory disease, chronic pelvic pain and infertility, she said. "It can have really devastating consequences for people, even though it is a treatable STI.
"And I think that doesn't always get communicated well."
The report also showed regional differences in the prevalence of condom use. Provinces and territories above the national average included Ontario and Alberta (both 73 per cent), the Northwest Territories (78 per cent) and Nunavut (79 per cent). Quebec (60 per cent) and Manitoba (65 per cent) fell below the national average.
In New Brunswick, Ontario and Alberta, the percentages of young people reporting condom use increased significantly between 2003 and 2009-2010 and did not decline in any province or territory.
"Geographic variations in condom use may reflect differences in the effectiveness of campaigns to promote their use and in the accessibility and-or affordability of other contraceptives," wrote the report's author, Michelle Rotermann. "In Quebec, for example, the province’s drug insurance plan reimburses the cost of some contraceptives, such as birth control pills."
Public education campaigns about the risk of STIs and condom use to prevent them are critical, said Waddington, adding that health-care providers like doctors could likely do a better job of talking to patients about condom use.
Flicker said children also need to be given age-appropriate sex education as part of the curriculum throughout their school years, so they have the information they need before they need it.
"I think that's where we're failing our kids, because a lot of the time in many provinces we don't start real sex education until Grade 9, and by then it's too late," she said.
"So the best I think we can do for our young people is make sure that the first time they have sex they're in a consensual relationship, that they feel comfortable advocating for their health rights and they're using condoms."