British heptathlon bronze medallist Kelly Sotherton has voiced her disapproval after Lyudmila Blonska's World Championships silver medal.
Sotherton (left) could not hide her displeasure at Blonska's silver
Ukrainian Blonska served a two-year ban after testing positive for steroids in 2003 and Sotherton is not happy she is winning medals ahead of clean athletes.
"I take the Paula Radcliffe stance on this," Sotherton told BBC Radio 5live.
"It's hard to trust someone who has failed a test. When they come back and are still improving, it's even harder."
Blonska, who set a new Ukrainian record of 6,832 points in Osaka, gave birth during her two-year absence from the sport.
"You still have doubts and 99% of us have doubts about certain athletes - and unfortunately she's one of them," she added.
"And in that time (she was banned) she had a baby, so she put her body through that and then comes back and performs out of her skin. I don't know how that's possible.
"When you compete against people who have failed drugs tests, and then they carry on improving when they're supposed to be clean - how can that be possible?
"I hope she's clean, I really do because it would please me and everyone else. We'll find out, we keep battling on but unfortunately you're always going to get the cheats."
Blonska was in the silver medal position behind Carolina Kluft from day one while Sotherton, who slid to fourth after a poor javelin, hauled herself into third with a gutsy 800m.
I know I'm clean so drug testing doesn't bother me
Her British team-mate Jessica Ennis finished outside the medals in fourth, meaning if Blonska had not returned to the sport two Britons would have been on the rostrum.
On the eve of the championships, governing body the International Association of Athletics Federations called for stronger penalties for doping, including a doubling of the ban for first-time violations to four years.
"I would support a four-year ban or a life ban (for testing positive rather than missing a test)," said Sotherton.
"It's very hard to come back from a four-year ban, and I don't think most people would. But it also depends on the severity of the drugs that are taken - there are different levels of drugs. There can be mistakes, there are genuine mistakes that happen."
Some 500 athletes have been drug-tested in the lead-up to and during the World Athletics Championships and so far all have been clean, the IAAF said on Monday.
The event will be subject to the largest anti-doping program ever conducted by world athletics' governing body, with more than 1,000 samples expected to be collected, up from 885 in 2005.
"So far there have been no positive findings," said IAAF medical and anti-doping director Gabriel Dolle, but admitted failed tests were almost inevitable. "We have to be realistic."
All medal winners are being tested in Osaka along with two to three others in each final, as well as randomly selected athletes in the heats.
Of the 558 tests so far, 363 have been blood samples and 195 urine samples, coming from 500 athletes.
But Sotherton suggested more rigorous testing procedures should be in place.
"I was tested, with a blood sample, before my event started and I'm completely all for that," she said.
"I know I'm clean so it doesn't bother me. After the event, the top three, and randomly selected other athletes, are urine tested. But it was only six out of 40 athletes, so some can slip through the net."