IOC backs boxers at Paris Olympics who failed gender tests
Imane Khelif from Algeria is set to fight on Friday in the women's under 66 kg category, while Lin Yu Ting from Taiwan has a first bout in the under 57kg division on Saturday.
"Everyone competing in the women's category is complying with the eligibility criteria," IOC spokesman Mark Adams told reporters.
"They are women in their passports and it's stated that is the case, and they are female.
"These athletes have competed many times before for many years. They haven't just suddenly arrived," he added, saying they had also featured at the last Olympics in Tokyo.
Khelif and Lin were both disqualified at the World Championships in New Delhi last year after failing to pass eligibility tests.
Khleif was disqualified hours before her gold medal bout over "elevated testosterone levels", according to her profile on the Paris Games information system.
Lin was stripped of her bronze medal at the championship after undergoing "biochemical" tests that were mandated by the International Boxing Association (IBA) under Russian oligarch Umar Kremlev.
The IBA was effectively expelled from the Olympic movement last year following a bitter dispute between the CIO and Kremlev, meaning the IOC has taken responsibility for organising the boxing at the Paris Games.
Adams said that determining eligibility criteria for women's sport was "incredibly complex" and should be done by federations.
"Everyone would love to have a single answer, yes or no," he continued, adding: "The federations need to make the rules to make sure there is fairness but also the ability for everyone to take part that wants to."