Doha - IAAF president Sebastian Coe on Friday hit a defiant note amid criticism of controversial new rules on women's testosterone, insisting they were "appropriate for the sport".
Track and field's governing body has come under the spotlight after unveiling the rules to counteract hyperandrogenism, the medical condition which causes women to produce high levels of male sex hormones.
The rules, which the IAAF puts under the heading "Difference of Sexual Development" (DSD), cover events from 400m to the mile because the IAAF's medical and science department says it has data showing hyperandrogenous athletes have an advantage over such distances.
When the rules come into effect on November 1, 2018, athletes such as South Africa's double Olympic champion Caster Semenya will only be able to compete if they take medication to reduce their levels of male sex hormones.
Semenya has long attracted debate because of her powerful physique related to hyperandrogenism.
The issue is controversial because it pits principles of fair competition against the rights of women born with the condition.
But Coe, speaking ahead of Friday's season-opening Diamond League meet in Doha, insisted the rules were fair and not something drawn up on a whim overnight.
"The regulations are very clear and they are really the culmination of 15 years of work here, scientifically reviewed," said Coe, who won two Olympic 1500m golds for Britain.
"I think there's a bit of a mistaken view that this is just one particular piece of work that has been showcased.
"That particular piece of work was in response to a very specific question that we were asked and that was about performance enhancement in testosterone.
"But 15 years of work across this was enough to give the council comfort that these regulations are appropriate for the sport."
Semenya's South African athletics federation on Thursday called the new rules "skewed" and said it would challenge them at the Court of Arbitration for Sport (CAS).
The controversy has also taken on a racial edge in the rainbow nation which was for decades run according to apartheid laws.
In relation to Semenya, Sports Minister Tokozile Xasa called the regulations "a very sexist, racial and homophobic... way to discourage her".
Paula Radcliffe, women's marathon world record holder and currently a member of the IAAF Athletes' Commission, described the rules as "a complete minefield".
But she insisted they were not made with Semenya as the target.
"I think it has been made with the IAAF trying to make it fair for the majority," Radcliffe told Press Association Sport on Thursday.
It was "completely unfair" to make Semenya the "poster girl" for the issue, Radcliffe added, insisting she had done nothing wrong.
"She's just the person winning by the furthest, so people are pointing fingers at her.
"If this was one person we wouldn't be facing this issue. We'd just let it happen.
"It's the fact that it's not and girls on the start line know they're never going to get a medal in an 800m. That's the bottom line."