Whether short or tall, blonde or brunette: sex robots come in all shapes and sizes. And one firm is floating the idea of a new variety of doll: transgender.

Realbotix are makers of sex robots, which have sparked a debate in recent years on the future of sex and how technology will affect our relationships. The robots are fitted with AI technology and tailor-made personalities, and can simulate conversations.

A director at the firm, based in California, told The Sun that a 'transgender' robot is on the cards.

"We do believe there is a market not only for transgender, but for any other sexual preferences of gender," Guile Lindroth, who runs AI at Realbotix, told The Sun is a strangely worded quote.

Unfortunately for Realbotix, creating a trans sex robot is impossible. What they mean by "trans sex robots" is dolls that feature detachable genitalia, such as a penis for feminine sex dolls.

Christine Burns MBE, a trans rights activist, told the newspaper that such dolls promote a damaging idea of the "she male" and bear "no resemblance to everyday trans people". Burns added that the dolls reinforce the idea that trans women are sexual objects.

The saying goes that gender is what is between your ears, while sex is what's between your legs. A person's gender identity is based on their personal sense of how society's ideas of masculinity and femininity relate to them. Therefore, "man" and "woman" are both gender identities. Sex, meanwhile, is the classification of a person as male or female. This is assigned to us at birth based on our external anatomy. Think of the moment when a doctor tells new parents if their baby is male or a female based on their genitals. Most people assume that a person with a penis will grow up to be a man, but this isn't always the case.

Someone might identify as trans if their gender expression doesn't match up with the gender they were assigned at birth. Those who don't identify as exclusively as a man or a woman might choose to use words like non-binary or genderqueer to describe their gender identity. A non-binary person may use the pronoun 'they' to reflect this.

For these reasons, a robot cannot be transgender. Because, no matter how good their programming, robots don't have a human consciousness or the self awareness to have an identity. And if sex robots did have consciousness, then we would all be in a lot of trouble.