Women’s sporting groups are increasingly concerned about biological males participating as females in their codes.

Northern Beaches Mermaids BG Volleyball Association president Nicole Esteves said she was very welcoming of transgender players, but felt it would be fairer if they played in existing mixed game competitions where both sexes already play together.

The club makes a point of telling new members it provides a “safe environment for women to play volleyball so they feel emotionally secure and comfortable within the sport environment, protected from physical and emotional harm”.

“It’s okay if you are signing in to a mixed competition and there are two boys and three girls and so on,” Ms Esteves said. “We want to be fair to everyone, for everyone to be included.

“In the women’s only games, they have a lower net. Someone born as a male can hit the ball much faster. They are physically stronger and they know that. What is happening now is some females don’t want to play because they don’t want to risk injury through lower nets against statistically stronger players. They are playing because they want to have fun.”

Scientifically, males have a greater advantage over females when it comes to strength, stamina and endurance. This puts women at risk and it creates an unfair playing field. Time and again the results speak for themselves. Male athletes almost always outperform their female counterparts.

Binary spokeswoman, Kirralie Smith, said mixed teams are the best option.

“For team sports that already field mixed groups this is the best, fairest and safest option,” she said.

“For individual sports or other scenarios, a third non-sex specific category could be introduced or simply stick to sex-based sections.

“The science is clear, simply lowering testosterone does not remove all of the advantages of muscle mass and memory, bone density, lung capacity, blood volume and other factors that give males an edge over women in sport.”