A WOMAN sits on a chair in a Glasgow rehearsal room.

She weighs her words carefully, stopping and starting, as she recalls what happened to her as a six-year-old in Ghana. "I can still see my mum," she says. "I was held down, I was screaming, I was crying and she couldn't do anything. She was crying from a distance - which showed she didn't want to do it it."

These are not actor Janet Kumah's own memories. Rather they are the words of Genet, the real person she plays, whose name has been changed for the sake of anonymity, a woman whose genitals were mutilated in an excruciating ceremony when she was a child. They are verbatim words, recorded in an interview by director Cora Bissett, authentic and raw.

Genet was not the only woman Cora Bissett interviewed as part of her research for Rites, her new play dealing with the harrowing subject of female genital mutiliation (FGM). There were many more: not only the women who had experienced FGM as girls, but mothers who had arranged it for their daughters, police who had dealt with the issue, lawyers, social workers and teachers. Bissett and Mancunian performance poet and writer, Yusra Warsama, collaborated to carry out the interviews and weave them together into a challenging new piece of theatre: one that tackles shocking and difficult subject matter, yet also, if the performers' testimonies are to go by, is peppered with laughter as well as tears, triumph over adversity as well as trauma.

This is a rehearsal of the show, and Bissett is directing Janet Kumah's performance, trimming some of her lines for sense. Genet's sentences are disjointed, like real thoughts struggling to come together. "I wanted to call my mum," she says, "to ask what kind of circumcision I had ... But I couldn't. She's not very well." The real Genet, who now lives in London, didn't know what had been taken from her body, how exactly it had been mutilated, until she was in labour with her first child and the midwife asked her if she knew that she had been quite severely stitched. Up until then, she had thought she had only had one of the more moderate form of female genital mutilation.

The World Health Organisation classifies FGM into four categories: Type I being the removal of the clitoris, Type II, the removal or cutting of some of the labia and Type III, the most extreme, being infibulation, in which most of the flesh is removed, and what's left of the labia majora sewn together in such a way as to prevent sex or preserve virginity, and with often profoundly damaging effects on the woman's health. There is also a Type IV, which includes alternative practices such as stretching the labia majora. Genet, like many of the women interviewed for the play, had no idea which had been done to her.

Bissett has tackled difficult material before, when she created Roadkill (about human trafficking) and Glasgow Girls (a musical about the schoolgirls who launched one of the most powerful asylum campaigns of recent times), but this is perhaps her most harrowing subject yet. The idea emerged through conversations with the Scottish Refugee Council, who had helped with research for her previous plays. When, after Glasgow Girls, she asked the SRC if there was a "new story" she should tackle, they mentioned the increasing numbers of girls presenting with FGM. "They said," Bissett recalls: "'We feel that this is a really urgent issue, because Scotland is shifting so drastically at the moment and we're not very well equipped to deal with cultural practices that we've not been familiar in the past'."

Worldwide, some 125 million girls and women are estimated to have had FGM. We don't know how many survivors of the practice there are in Scotland, or how many young girls are at risk of it. Last year the SRC published their own report on the issue. They estimated that there were 23,979 men, women and children in Scotland who were born in one countries identified by UNICEF as "FGM-practising". The largest community potentially affected are Nigerians, followed by Somalis, and also people from Egypt, Kenya, Sudan and Eritrea. The number of children born to potentially affected communities in Scotland has increased five-fold over the last decade.

Almost as soon as Bissett decided to tackle this subject, she knew she wanted to work with a writer "linked culturally to a background that was practising FGM". In 2013, she had met Yusra Warsama, a Mancunian poet and performer of Somali heritage, while they were both involved in The Bloody Great Border Ballad Project at the Edinburgh Fringe. In Somalia, FGM is practised on 98% of girls, with 90% receiving the extreme Type III. Warsama had contact with people who had experienced FGM in some form, within both her extended family and wider community. She and Bissett shared a desire to explore the "grey areas" of the issue. Both wanted to avoid the idea of victimhood. "We knew," says Bissett, "we didn't want to present on stage a kind of shock horror story of a poor little girl."

Bissett says that as a woman brought up with a "liberated, feminist mindset", her knee-jerk reaction was horror. "Every bone in your body reacts against it, on a child's rights level, on a women's rights level. To the very marrow of your being it just feels so clearly wrong." However, in researching the play, she tried to put herself inside the minds of those who practise it. "I try to think, 'What would happen if I was born in the Gambia however many years ago and everyone else in my village did it and my mum felt that this was the only way to make me marriageable or to make me respectable and if it wasn't done I would be scorned upon, seen as dirty and entirely unmarriageable? Would my mum do it to me and would I do it to my little girl?' The answer is probably yes."

Though Bissett is clear in her mind she wants the practice to end, she does not want the play simply to condemn FGM or demonise those involved. Rather, she is interested in exploring the "complexities around it", and "those political and race-related questions about how a multicultural society lives and works together".

Warsama sits on the edge of the rehearsal studying the text as Kumah performs. She is in Glasgow on a flying visit, for a day. The poet and actor is busy with countless other projects, including rehearsals for The Vote, a play to be live-televised on election day, starring Judi Dench. Born in the United Arab Emirates to an Islamic Somali family, she was 18 months old when her parents moved from Abu Dhabi to settle in Manchester in the UK. Given her background, Warsama notes, her reaction to the idea of FGM is not, as it might be for some, to say: "How abhorrent. What is this horrible thing?" She grew up knowing what FGM was.

Like Bissett, Warsama is not looking to accord blame, or demonise, but to create a play that asks questions, such as: "When does the victim become the perpetrator, or the perpetrator become the victim?" Most mothers who arrange for their daughters to have FGM are victims themselves. Warsama quotes feminist anthropologist Janice Boddy who once said that "understanding the [FGM] practice is not the same as condoning it". "Of course you don't condone FGM," says Warsama, "but you have to understand all parts of it and all aspects of it."

Both she and Bissett pursued their own contacts and interviewed people from across the UK and farther afield, including the United Arab Emirates. What they discovered as they collected their interviews is that across the UK the degree to which communities continue the practice - and how they feel about it - varies enormously. "You can be speaking to a group of Somali women in Cardiff, second-generation," says Bissett, "who have entirely left the practice behind and feel that the media have really blown it out of proportion. But you can also speak to a FGM survivor in Glasgow who is saying, 'I've got no-one to talk to, I don't know where to go and I don't know how to get help. I can't even speak to my family about this.' Everybody's experience is quite different."

Not only does Warsama have family in the UAE who have had FGM, she also has friends in the UK who are social workers practising in the affected communities. All this means she has a textured view of it. Among the stories she cites is one about a malicious call that was made about a woman who had returned from a visit to her home in Africa, which led to police and social workers taking way her child and examining her. A parent herself, Warsama feels a great deal of empathy for such a mother. "I wouldn't want my child to have a part of her body that she has no awareness of examined. I wouldn't want that conversation coming into my household." She worries too about racial profiling, or that assumptions will be made about people within affected communities.

Though some of the women she spoke to in the course of her interviews were traumatised by the experience, others were not. "They felt," she says: "'Hold on a minute, I'm not downtrodden or disempowered. Before you liberate my vagina, my vagina is my own'." Nor, as the play shows, is FGM always submitted to reluctantly. Among the many real characters featured is an American woman who has elected aged 21 to have FGM as a way of reconnecting to Sierra Leone, the home country she is returning to.

Sometimes, Warsama says, people from her community ask her why she is tackling this subject. Her 19-year-old sister, a dynamic, headscarf-wearing, "outwardly Islamic-looking" young woman, asked: "What are you doing that for? Why this aspect of Somali culture, not some other?" It's a feeling she's observed more widely within the community. "It's not that they don't want to talk about it or to silence and subjugate these women. It's a silence that says, 'We come from such a beautiful culture. Of all the things you could speak about, why are you doing this?'"

The play, among other things, hopes to provoke conversation. The more the issue is talked about, particularly within the affected communities, the more chance there is of change. Many of the women, like Genet, do not know what happened to their bodies. They do not know what flesh was removed. Such is the level of secrecy and taboo around the practice, it has never been discussed. "This is why it's so difficult for a lot of survivors," says Bissett. "A lot of the women say, 'I don't know what type I had, I just know I had bits removed'."

Among the many narratives Warsama and Bissett collected is that of a woman from the Gambia, where 80-90% of women have FGM. Paida Mutonono, the actor who plays the role, describes her character: "She came over to the UK after having it performed at the age of seven or eight. But it was only when she was at a university lecture that she realised what had happened to her. Her journey is the vehicle through which we explore, because she starts asking questions: how, why where does this happen, who does this happen to?"

Mutonono grew up in Zimbabwe and moved to Essex in the UK in her mid-teens. Though Zimbabwe doesn't have a high incidence of FGM, she was aware of a Type IV form of it going on in her family, to distant members, girl cousins. "There was talk of being taken out of the village to a house or about ceremonies," she says. She remembers when her cousin talked about it, she wasn't aware of it, and asked her what it was. "You don't want to know," her cousin replied. What was practised was not "cutting" but a tradition in which the vaginal lips are pulled to appear bigger and more "womanly". Mutonono notes this is at the "opposite end of the spectrum to infibulation, but it's still invading a little human being's choice and space".

Back in the rehearsal room, Janet Kumah, reruns the lines of her Genet monologue. "I don't feel any anger for my mother," she says. "At all." Those words hang in the air, difficult to deal with. Bissett notes that this is often the case. A great many survivors appear not to blame their mothers. "The West ," says Bissett, "deems the practice child abuse, but they don't see it that way. They say, 'My mother did this thing that she thought was the best for me. Yes it has had a negative implication, but I know it wasn't done out of badness. I know why it was done'." Yet Bissett asks Kumah to channel some anger into her speech. She is convinced that it is there, somewhere. "There is pain," says Bissett, "and there is nowhere to put it."

There is levity as well as gravity among the cast present today. Actor and comedy writer Elena Pavli is playing 11 different roles, and if there's a joke to be found, she says, she'll "mine it". There are, she notes, characters that are "absolutely hilarious", scenes that are hard to get through "without laughing". But not only that, as a cast, they quickly had to drop any barriers they had; taboos were rapidly broken. "The minute you pick up the script and have a go they go out the window," says Pavli." I don't think I've said 'the vagina' so many times in a play."

Paida Mutonono agrees: "I think it's said even more times than in The Vagina Monologues."

One message that comes across is that female genital mutilation is not something that can be treated in isolation. Rather it is, as both Warsama and Bissett point out, a practice that exists on the spectrum of gender violence, and also a tradition that exists for controlling women. As Warsama puts it: "One of the hardest things of this piece is that it has made me realise and accept that the world we find ourselves in is not very fair to women, particularly brown girls. It's really hard to say that and know that, but when it comes down to it we know there's an imbalance in society, we know that these things go on."

The battle against FGM has been going on for decades. The practice is now outlawed in most countries, but still continues. As Warsama puts it: "A shift has been happening, slowly but surely, over the last 30 years." In a great many cultures, young girls tend to be against it, even if older members of society are not, and the practice is less common among adolescents than their middle-aged counterparts in most of the 29 countries in which it occurs. Nevertheless if current trends continue as many as 30 million girls worldwide are estimated to be at risk of being cut before their 15th birthday.

That said, the show's creators believe that most people want change. Warsama recalls: "Everyone we talked to was saying that FGM is bad and we would never ever do it again. We've not come across anyone who is willing to practise it or continue the practice, so there is a beautiful unifying theme. Whether they've experienced it or worked in frontline services, whether they're lawyers - whoever they are, everyone is trying to stop this thing."

Rites tours Glasgow, Manchester, Bristol and Edinburgh from 5 to 30 May 2015, www.nationaltheatrescotland.com

The National Theatre of Scotland and Contact will be working to make Rites accessible to affected parties in each community it plays, including frontline services and other professionals. There will be women-only matinees and post-show discussions with a local panel at each venue, as well as CPD events for those working in areas such as healthcare, education and social work. Visit the website for full details.