A woman has spoken of her concern after twice encountering a "naked man" in the female changing rooms at the UEA Sportspark.
The woman, who did not wish to be named, said on two consecutive weeks she saw an individual with exposed male genitalia in the female facilities.
But she claims when she highlighted her concerns she was told by staff that it would be discriminatory to query the person.
But a Sportspark spokesman confirmed the centre does not allow men in women's changing spaces and vice versa.
But the woman said her and a friend she was visiting with were both left feeling "vulnerable and uncomfortable".
She said: "I was made to feel as though just anybody can walk into whatever changing room they like.
"If I know for sure that somebody is a transgender woman, I have no problem sharing a changing room with them - but how am I to know until they are undressed?"
The woman said a viable solution would be for safeguarding checks to be carried out on members to ensure women feel safe using female-only facilities.
But added: "I think it should come down to biology - if you have male biology you use the male changing rooms and female biology use female rooms."
A UEA spokesman said: "We recognise that this is a complex issue, so continually review our facilities across the centre.
"We take all aspects of privacy, decency, health and safety of the centre and its users very seriously.
"These include separate accessible changing, self-contained cubicles as well as group change spaces.
"We also provide self-contained shower facilities in addition to our communal changing areas.
“We fully recognise our legal responsibilities and do not allow men to use the female changing rooms, or women to use male changing rooms, and we ask people to use the changing spaces that are appropriate to their circumstances."
The issue of access to women-only spaces has been the subject of recent debate, following the case of Isla Bryson, who was convicted of raping two women while called Adam Graham but who now identifies as a woman.
Bryson was sent to a women's prison, prompting an outcry.
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