LOS ANGELES • US Olympic team boxer Virginia Fuchs has been cleared of a doping violation, after the United States Anti-Doping Agency (Usada) determined that banned substances in her sample had been transmitted during sex with her boyfriend.

The 32-year-old flyweight had tested positive for two substances prohibited by the World Anti-Doping Agency (Wada) in an out-of-competition urine test on Feb 13, Usada said in a statement.

"The low amounts of letrozole metabolite and GW1516 metabolites detected in her sample were consistent with recent exposure to the substances via sexual transmission," Usada said.

The body added Fuchs' partner had been using therapeutic doses of the two substances and that she bore no fault or negligence for the adverse finding and would therefore not be banned.

"We strongly believe this case and others like it, including meat contamination and prescription medication contamination cases, should be considered no violation," Usada chief executive Travis Tygart said.

Fuchs narrowly missed out on qualifying for the Rio Olympics in 2016 and has now set her sights on the delayed Tokyo Games, which are scheduled for July 23 to Aug 8 next year.

"This has been a huge lesson for me and now that is over, I'm fully focused on preparing for Tokyo," she tweeted.

Fuchs also told local TV channel Fox 26 she had "no idea you could get contaminated through intimate contact".

Bubba Nickles, who is on the US Olympic softball team, is the only other known American athlete to test positive for a banned substance as a result of exposure following sexual intercourse.

In March, Usada also cleared the 22-year-old of any potential doping violation.

The usual punishment for the use of banned substances is a four-year suspension from all Wada-compliant sports.

REUTERS