When I was at boarding school, about age 13, I remember listening to the rest of the girls in my house talking about their periods. They'd all started, and I was embarrassed about the fact that I hadn't. I was so ashamed not to have officially started puberty yet, that one day, when they asked me if I'd got my period, I lied. I felt pressured, and told them I had so I could revel in being exempt from swimming lessons once a month like the rest of them.

But the lie didn't stop there. I so badly wanted to believe it was true I even told my mom my period had started, and while I look back now and think it's stupid, I think I just wanted to conform and feel part of the club.

Two years later, I was 15 and my period still hadn't arrived. It was playing on my mind, not least because my mom had needlessly been buying me sanitary products, which had been lying unused for the past 24 months. So one day, when my mom drove me to hospital after I'd broken my hand, I blurted it all out.

Natasha Bishop by Lucy Davies

I told her the truth, and while I was scared she'd be angry about all the wasted tampons, it was a relief to let it all out. In reality, she wasn't in the least bit angry, and actually found it quite funny that I'd lied. She, like me, assumed my missing period was no big deal; I was probably just a late developer.

But a year later, when my friends began losing their virginity and I still hadn't had my first period, I grew more concerned. I didn't even know if I could have sex if I'd never had a period (sex ed lessons never really covered that), which made me panic about being left behind even further. I felt like I wasn't a real woman.

So we went to the doctor, and after a lot of back-and-forth with several medical experts who couldn't understand what the problem was, I was sent for an ultrasound, where they spotted something unusual.

I had been born with no uterus, no cervix, one ovary and only a partial vagina.

"Oh, you don't seem to have anything inside you," the doctor said, which was a pretty insensitive way of telling me I had been born with no uterus, no cervix, only one ovary and a vagina which looks normal on the outside, but doesn't really exist inside. It's basically just a wall in there.

Eventually I was diagnosed with Mayer Rokitansky Küster Hauser Syndrome (MRKH), an incredibly rare disease caused by a problem with development in the womb. But it took a while to get there. They sent me for test after test and scan after scan to get the final diagnosis, and I even had to undergo a hormone test to check that I was actually female.

When you're 16 and your gender is called into question, it's hard to deal with. You don't really know who you are as it is, without worrying about a huge part of your identity being to brought into question. It's psychologically damaging. They found out that I was biologically female, but it didn't stop me wondering what the point of my existence was. I kept thinking, Am I a real girl if I can't have sex and I can't carry a child? It was horrible.

Natasha Bishop by Lucy Davies

There was a lot of information to take in; there's a slim chance my one ovary could be viable to produce eggs, but I won't find that out until I start looking into IVF when I'm ready to have children. It also became very apparent that I couldn't have sex like a normal person could.

My GP drew it all out for me and talked me through my options; if I wanted to have sex I'd need to undergo a "dilation process" which involves a very heavy, clinical-looking medical dildo and would be incredibly painful.

I pushed my MRKH to the back of my mind while I did my exams, but there were times it would creep up on me, like when I'd be at a party and would watch all my friends go off with boys. I couldn't help thinking that even if I wanted to do that, I couldn't. It made me not want to go near boys at all.

I kept thinking, Am I a real girl if I can't have sex and I can't carry a child?

Eventually, though, a friendship with a guy from school turned into something more, and I was forced to address it. After two months of dating, it got to the stage where sex was being mentioned, so I just had to come right out and tell him. I was terrified he wouldn't want to be with me if I couldn't have sex with him yet, but he was amazing and wasn't fazed by it all.

We'd been together for about a year by the time I was referred to the Queen Charlotte Hospital in London to have my dilation treatment. At 18 years old I had to go and stay in the hospital for a week where I regularly inserted the dilator for eight hours a day. It was excruciating.

The dilator feels like a heavy bottle of water, and you start with one half the thickness of a pen, eventually working up to one the size of a penis, so you kind of "create" a vagina for yourself that can accept penetration.

You have to use this horrible gel stuff that numbs everything because it's so painful; you have to move and twist the dilator, which was not only complete agony, but makes you feel dirty as well. Obviously it shouldn't, but it does. The whole experience is long and complicated, clinical and horrible.

I ended up with bruising all over my vagina, it bled and was raw, but you can't stop. That's the worst thing. You have to do it, but it's not like you're doing it to recover from an illness or anything; you're only doing it for yourself. You certainly realise the extent of your own determination after a week of self-inflicted pain like that.

Luckily, I had a nurse called Nuala there to help me thorough it. She was hilarious, and I felt comfortable around her which was important because it's such an intimate and emotional thing. I remember every day I would cry for the first hour, and then I'd be laughing hysterically at how ridiculous the situation was, and how hilariously embarrassing it was that all my friends and family knew I was in hospital going through all this pain just so that I could have sex.

Nuala helped me with my worries about what sex would feel like for the first time by telling me to get myself a beautiful set of lingerie that made me feel confident and powerful. So I did, and when it eventually happened in Paris (my boyfriend studies at film school there, so it was pretty awkward waving goodbye to my family for that trip when they knew exactly what we were going to be doing), the lingerie really helped.

I remember standing there in my underwear and feeling so powerful.

I remember standing there in my underwear and feeling so powerful that I was finally able to do this for myself, when I was ready. I guess that's a bonus in some way; I know a lot of my friends regret losing their virginity and wish that it had been something more special. For me it was, because I knew it was with someone who truly loved and supported me.

The worst thing about MRKH is that, because I'm in a long-distance relationship (my boyfriend still lives in Paris while I'm studying at Oxford, so we only see each other once a month) I still have to use a dilator in preparation for every time I see him. My vagina is like a muscle, basically, and if I don't "exercise" it regularly enough, it'll go back to how it was before.

It's not like I want to have a one night stand — I'm in a happy relationship — but it's the fact that I'll never get the choice or the sexual freedom to do that. That in itself makes me realize how lucky we are to live in a society where women have such liberation now. Years ago we didn't have that, and in some countries that's still the case. In those places, women are defined by their ability to have a child and their ability to make a home, and I can see how that can be so damaging because if I had been born into any of those societies, I would be regarded as "useless."

Natasha Bishop by Lucy Davies

I feel so lucky that I'm dealing with MRKH now, in a first world society where having a career and so many other things are just as important for women as their sexuality and their ability to have a family. For a while I didn't believe that; I felt so bereft, like I wasn't a woman in society's eyes. I can't have a child, I can't have sex, what am I supposed to use my body for? Is there any point in me having a body?

But I don't think like that now. It took me a while to get there, but now I know what I can achieve and I feel lucky to have been born exactly as I am."

* Tasha Bishop has set up The Pants Project, a non-profit organization which sells underwear donated by various designers, and donates 90% of the profits to Fertility Network UK, Britain's leading patient infertility charity. You can check out more from The Pants Project on its Instagram and website.

Catriona Harvey-Jenner Digital Features Editor Cat is Cosmopolitan UK's features editor covering women's issues, health and current affairs.

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