J. K. Rowling has been accused of being transphobic after posting a controversial tweet about menstruation.

The 'Harry Potter' author sparked anger online after she reacted to an article titled 'Opinion: Creating a more equal post COVID-19 world for people who menstruate'.

Her tweet read: '''People who menstruate.' I'm sure there used to be a word for those people. Someone help me out. Wumben? Wimpund? Woomud? (sic)''

The 54-year-old writer subsequently defended her comments on the social media platform, after being inundated with criticism.

She also insisted she loves the trans community.

Rowling wrote: ''If sex isn't real, there's no same-sex attraction. If sex isn't real, the lived reality of women globally is erased. I know and love trans people, but erasing the concept of sex removes the ability of many to meaningfully discuss their lives. It isn't hate to speak the truth. (sic)''

Rowling revealed she's researched the issue over the ''last three years'' and rubbished suggestions she doesn't have any knowledge of the subject.

She said: I've spent much of the last three years reading books, blogs and scientific papers by trans people, medics and gender specialists. I know exactly what the distinction is. Never assume that because someone thinks differently, they have no knowledge. (sic)''

Rowling also revealed she'd discussed the subject with people within the LGBTQ community.

She wrote on the micro-blogging platform: ''One of my best mates just called me. Self-described butch lesbian. It was hard to tell, because she was shouting quite loudly, but I could just make out 'F***ING YES!' (sic)''

She later added: ''The idea that women like me, who've been empathetic to trans people for decades, feeling kinship because they're vulnerable in the same way as women - ie, to male violence - 'hate' trans people because they think sex is real and has lived consequences - is a nonsense.

''I respect every trans person's right to live any way that feels authentic and comfortable to them. I'd march with you if you were discriminated against on the basis of being trans. At the same time, my life has been shaped by being female. I do not believe it's hateful to say so. (sic)''