People for the Ethical Treatment of Animals (PETA), has accused German international Thomas Muller of forcing his horses to perform "unnatural sexual acts" at his farm in order to obtain their semen.
As per British publication the Daily Mail, the Bayern Munich forward sells a dose of their frozen semen for as much as $225.
Muller and his wife Lisa, who is a semi-professional equestrian and competes in a number of horse dressage exhibitions and other events, are the owners of an animal estate in Germany.
The non-profit organisation's allegations against the World Cup winner came a week after the 32-year-old player announced that one of the horses in his stable, named D'Avie, will take a few months to recover from an injury.
"Unfortunately, we have bad news. Our D'Avie will not be available in the next few months. Unfortunately, he slipped during a test attempt to prepare for breeding season and fell dramatically on his side", Muller said.
"He sustained an injury to the hoof area and will need complete rest for the next few months. He's a tough guy, and it could have been worse", he added.
PETA reacted to the news by labelling the practices at their farm as "unnecessary, before dubbing the couple as "self-proclaimed horse lovers".
"It is horrible that self-proclaimed horse lovers force animals in their care to perform unnatural sexual acts to profit from it", she said.
"The injuries D'Avie suffered under the supervision of Lisa and Thomas Muller were preventable and unnecessary".