The description has raised the ire of customers, forcing the company to make changes in the wording used to advertise the bikes on the company's website.
The children's bikes with the offensive wording includes the Milazo Boys' 20-inch Matt Black BMX Bike-in-box 408 and Milazo 20-inch Bike-in-Box 725 BMX Camo.
In a spelling mistake-filled product description, it recommended the bike for children 8 years and above and listed a number of features and benefits.
They included a front and rear double safety hand-brake system, for more speed and accuracy, and a strong steel frame and fork with safety reflectors.
"Very fast Quick release brake, just pressing the button, so easy even for a girl [sic]."
The sexist description has sparked a flurry of customer complaints.
The company has removed all reference online to being easy enough for girls to use, and in the past 12 hours deleted all mention of the quick-release brake function.
Today The Warehouse apologised to customers on Facebook, saying the wording was unacceptable and did not represent the company's values.
"We know boys and girls are equals, and can do anything," read the post.
"This language, which came from an overseas supplier, is unacceptable and isn't what we believe at all. It's not in our values.
"Because of this, we really appreciate that our customers called it out."
The company said it did its best to catch all the many thousands of product descriptions to make sure they met standards.
"We missed this one, and we truly apologise."
