Transgender women will be banned from competing in female rugby union and rugby league under new policies approved by the Rugby Football Union (RFU) Council and Rugby Football League (RFL) Board.
The RFU Council voted in favour of updating its gender participation policy for rugby union in England from the start of the 2022/23 season with 33 in favour, 26 against and two abstaining.
The policy change only permits players to participate in the female category of the sport, "if the sex originally recorded at birth is female."
Speaking about the decision, RFU President, His Honour Jeff Blackett said: "Inclusion is at the heart of rugby values and we will continue to work with everyone to keep listening, learning and finding ways to demonstrate there is a place for everyone in our game.
"We know that many will be disappointed by this decision however, it has been based on all the scientific evidence available."
The RFL Board has also approved a new gender participation policy to take effect from August which states that players in all 'contact' rugby league, from U12s and above, will "only be permitted to play in the gender category of the sex that was originally recorded at birth".
The RFL said the new policy "reflects both the requirements of the Equality Act 2010, which defines rugby league as a 'gender-affected activity', and significant developments in this area over the last two years."
The RFL added that they are "committed to providing and supporting opportunities for everyone to be actively involved in the sport... however, it is important that the playing opportunities provided are safe and fair for all participants.
"This means that, when determining the eligibility criteria, a precautionary approach needs to be adopted in respect of contact variations of Rugby League, so that safety and fairness are considered alongside the principle of inclusion."
Rugby vote on transgender women a 'massive step backwards'
The RFU recommendation comes after it conducted an extensive review of its gender participation policy for English domestic contact rugby.
Transgender women like Alix Fitzgerald, who plays rugby union for the East London Vixens, will now effectively be banned from the sport in England.
She told Sky Sports before the vote: "I'll be honest with you. If I thought for one moment I was a danger to the people in front of me or the people I play with, I wouldn't do this. I have no desire to hurt anybody at all, accidentally or not."
The 54-year-old is one of seven transgender women in England who had previously been permitted to play rugby by the sport's governing body.
She added: "I am not the largest person on this team, I am not the strongest person on this team. That argument is a very dangerous one for rugby to go down, simply because, who's big enough? And who's too big?
"There are people on this team that are bigger than me, so if I'm too big, are they too big? And that's just not right because rugby is a game for all shapes and sizes."
Kat Salthouse, who is the vice-chairwoman of the Vixens and plays alongside Alix, described Friday's vote as a "massive step backwards".
"In my four years of playing alongside Alix, I've never had any safety concerns," she said. "Alix is no more of a risk to myself, my team-mates, or our opposition than we are to ourselves playing a contact sport.
"We're in a society now where we need to be more open and accepting of the people around us."
Green: It's a dark day | McAnena: A return to common sense
Susie Green, CEO of UK LGBTQ+ charity Mermaids, said the decision is a 'huge blow' and went against the idea of inclusivity in sport.
"Disappointment, and how this is going to disappoint so many young people who enjoy playing sport, enjoy being themselves," Green told Sky Sports.
"This is going to create a situation where you either have to choose being yourself or choose being able to participate in a sport. That's surely not the point of sport.
"Sport is meant to include everybody, every young person and adults of course can participate in something so important to well-being.
"It's a huge blow and a really dark day to be honest."
Fairplay For Women's Fiona McAnena meanwhile agreed with the ruling and encouraged other sporting governing bodies around the world to follow suit.
"We're delighted to see a return to common sense," McAnena told Sky Sports. "Who would have thought we'd have to have a vote about whether the female category should be only for females?
"I think this is really going to help the RFU to grow the women's game which is what they want to do.
"The onus is now on England rugby and all governing bodies of sport to make sure they look at their whole sport and find a place for everyone.
"What they shouldn't be doing is looking at the female category and finding reasons to let people who are not female into that category because that compromises women and girls."