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Can you ever truly come to terms with desperately wanting a child, but never having one?

It's a simple question that is deceptively difficult to answer. It's one my husband and I have asked ourselves, as we've struggled to start a family of our own.

And we are far from alone. It's thought one in four women born in the 1970s will reach 45 without giving birth. For those born in the 1960s that figure is already running at one in five. The vast majority are childless through circumstance, rather than choice.

Find out more Listen to A Family Without a Child on BBC Radio 4 on Friday 15 August at 11:00 BST

The programme, presented by Sangita Myska (above), will be online shortly after broadcast To read more about the issues of childlessness and infertility, visit the following websites: Relate

Infertility network

Gateway women

Even so we hear very little from them.

Theatre executive Jessica Hepburn is 43 and has been trying to have a baby for nine years with her partner, Peter. "It's like a bruise," says Jessica about the emotional impact of failing to have a biological child, "whenever you press it, it hurts. I often wonder what our kids would have looked like - Peter's hair, my eyes? I always imagined motherhood would be part of my life. Creating a child with the person you love - it's a very natural, strong desire for me."

It's one Jody Day, who began trying for a baby with her husband when she was 29, also felt. "At the time, I dedicated everything to having a family. At no point did the idea that it wouldn't happen, come to me." Now aged 49, she says time has helped her cope with the grief of not conceiving. "People come to me and they say, can you get over childlessness? And I say, it's not the flu - it's a lifelong thing. I am happy now, but, not having children broke my heart. No doubt about it, it broke my heart."

The stress of trying and failing to have a child led Jody into a bout of depression. "There was one day that I lay on the floor of my flat and thought, I will stand up when I can think of a compelling reason to do so. I kept asking myself 'what is the point of my existence?' I had to go very deep to find a reason to carry on."

Image copyright Jessica Hepburn Image caption Jessica Hepburn has had 11 rounds of IVF

Jessica, whose infertility is unexplained, chose to undergo 11 rounds of gruelling IVF treatment, at a cost of £70,000. She has only recently paid off the debt.

She chose not to tell her friends and family everything she was going through, including a life threatening ectopic pregnancy and several miscarriages.

"I kept it absolutely away from my colleagues and I would go and have egg collection very early in the morning and be back at my desk by 10am. My ectopic pregnancy was discovered at three months and even though I was rushed to hospital, no one knew the full story. I also had a miscarriage at nine weeks and several biochemical pregnancies, which are very early miscarriages, and then of course a few unsuccessful rounds of IVF as well. Because we always felt so close, I couldn't give up."

Jessica says that along with the disappointment, she also felt ashamed about what was happening to her. "I think shame is a massive factor in not being able to have a child - feeling just so desperately that you want to be like everybody else, but somehow you're not, and feeling ashamed that you can't do what everybody else does. You're hiding the fact that you're disappointed that your life hasn't worked out how you hoped."

For women like Jessica, coping with a sense of loss can, albeit unwittingly, be made worse by the reaction of others - inviting the empathy while eschewing pity, there's a difficult balance to strike and it has the potential to strain close relationships.

Image copyright Simon Fairclough Image caption Jody Day founded Gateway Women for childless women

Jody Day's marriage eventually broke down and by the time she had recovered from depression she realised her circle of friends - who'd got pregnant with ease - had moved in another direction. "My contemporaries were all having children. I think that's when it started to get difficult. Because I realised that I had become a sort of social pariah as a single childless woman.

"And it was a dawning realisation that I just wasn't getting invited anywhere anymore. Our lives had taken very different paths. It's very hard to accept that. There's so much unspoken stuff here. It's a taboo to talk about it. And I think it's really, really hard to admit."

Embedded in the English language are a plethora of offensive labels: Barren, selfish, spinster, career woman (we never use career man).

After her divorce Jody dated other men, but by 43 she experienced early menopause. She says it was that biological change that helped her to come to terms with her childlessness, "I've done the journey of wanting to be a mother. I've come out the other side of it. I'm post-menopausal now and goddess oestrogen has left the building. I don't crave a baby any more - that part of my life is over."

The age of mothers has been rising since 1975 in England and Wales, according to the ONS

Possible factors mentioned by the ONS include: increasing importance of a career, instability of partnerships and labour market uncertainty

Fertility rate for women aged 40 or over has nearly trebled since 1991

The average age of a mother in England and Wales was 30.0 years old in 2013. In Scotland the latest figure was 29.7 and in Northern Ireland it was 30.1, both for 2012

Reaching this point has given Jody a sense of freedom, and the time to carve out a new identity. She has three masters degrees and is training to be a counsellor - specialising in adolescent and child psychology.

Yet she still meets people who struggle to know how to react to her situation. ''Often people get focused on the idea that we've chosen this in some way or that we just haven't done the right thing - and get stuck for what to say.

"The very first time was when I was still married and still trying to conceive. I was at a cocktail party when a woman comes over to me and says, 'so you know, if you don't manage to get pregnant, would you consider adopting?' And I was just taken aback and I replied 'No... I... I don't think so'. We were suddenly in this incredibly intimate conversation, without warning, and she looked at me and said 'but then you obviously don't really want children then' and walked off. "

In her chatroom, Jody says, women describe these all too frequent - and entirely inappropriate - reactions as "bingos".

Image copyright Paula Coston Image caption 'All the childless women I know feel very self-conscious about it,' says Paula Coston

The suggestion that people who fail to have biological children should automatically choose adoption as a substitute is at best unthinking and at worst reckless. Experts often advise that parenting adopted children is a rewarding and sometimes challenging experience that potential adopters should think about carefully and commit to fully. The process is rigorous and emotionally challenging and is a unique path to parenthood in its own right.

Novelist Paula Coston, 59, had a high-flying career in publishing, when offices still resembled an episode of Mad Men. Her life brimmed with glamorous parties and exotic travel - but not the right man with whom to start a family. She's now experiencing the isolation that Jody describes, a second time around.

"My friends are at that stage now where their children are about to have a child or certainly thinking about it and so I'm bracing myself for this new sort of wave of the experience to come over me really."

Her life is busy with work, family and friends, but she worries that the difficult emotions she dealt with years ago may bubble up again. "I have a feeling that I will feel yet more distance from the people I know who are becoming grandparents. I will not only not be able to relate to them as parents but I will not be able to relate to them as grandparents either. I will be aware, I think, that there's a bit more distance between me and that whole side of family life."

Image copyright PAULA COSTON Image caption Paula Coston spending time with her siblings' children

As a single, childless, older woman, in some ways Paula gets a particularly raw deal - sidelined for failing to snag a partner, failing to have children and then daring to age.

Paula argues that, society as a whole, tends to neglect childless women - and to its cost. "As a group we are increasingly cut off and underused," says Paula. "Where are the mentoring schemes, how can we hand down our skills, why aren't our opinions about children's futures taken into consideration?

"We have great life experience and empathy that could really benefit others. I know I'd love to pass on my skills."

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Listen to A Family Without a Child on BBC Radio 4 at 11:00 BST on Friday 15 August. You can also hear it on the Radio 4 web page.