Ruba and Saqib both carry a gene for an incurable condition, which means their children have a one-in-four chance of dying in early childhood. They've already lost three. Ruba now wants IVF, to select a healthy embryo. Saqib is putting his trust in Allah. And some relatives want them to separate and remarry.

Ruba Bibi had not wanted to marry so young. She had planned to do A-levels and go to university, but before she had finished her GCSEs her parents arranged for her to marry Saqib Mehmood, her cousin, in Pakistan.

Born and brought up in Bradford, Ruba had visited Pakistan twice before the wedding - once when she was four and once when she was 12. She couldn't really remember the man she was now engaged to and had never spent time alone with him. He was 27 and worked as a driver. She was 17.

"I was really nervous because I didn't really know him," she remembers.

"I was really shy, I couldn't talk much and I hadn't ever had any interest in boys or anything like that. I was scared and asked my parents to delay things to let me finish school, but they couldn't."

After three months in Pakistan she was pregnant. She returned to Bradford two months later, shocked to be having a baby so soon. But also happy.

When their son, Hassam, was born in 2007 she excitedly called Saqib to tell him that all was well, although the baby seemed to sleep a lot and had trouble feeding.

"I just thought it was normal," Ruba says.

A few weeks later she went for a check-up, and as the GP watched Hassam moving she noted that his hip seemed stiff.

"She said she was going to refer him, but I thought it was something minor. They did some tests and then I got a call saying I had to come to the children's ward for his results," Ruba says.

"When I went in, the doctor told me it was very bad news. She gave me a leaflet and said he has this condition and it's very rare. It was too much for me to take in and I was just crying. I came home and rang my husband in Pakistan, who tried to calm me down. He told me that everyone goes through problems and that we would get through this together."

Ruba had no idea that both she and her cousin carried the recessive gene for I-cell, a rare inherited condition that prevents a child growing and developing properly.

Seven months later Saqib received a visa to live in the UK, and was able to hold his son for the first time.

"He said he looked like normal baby. He wasn't sitting or crawling, but my husband said some children were just slow," Ruba says.

She, however, could see a big difference between her son and other babies the same age. Hassam was growing slowly, and was in and out of hospital with chest infections. And as he got older his head increased in size.

When their next child, Alishbah, was born in 2010 tests confirmed immediately that she, too, had I-cell disease. She died at the age of three, towards the end of 2013 - just over a year after her elder brother.

Before getting pregnant a third time, Ruba consulted Mufti Zubair Butt, the Muslim chaplain at Leeds Teaching Hospital, to ask what her religion would make of screening during pregnancy - and termination if I-cell was confirmed.

He told her that it would be an acceptable course of action, but advised her to think very carefully.

"If you have this condition where the child is going to die in any case, or even if it doesn't die soon, it will have debilitating illness, that's sufficient reason to terminate before the soul enters the body, based on the sayings of the prophet," he said.

But he also said that she shouldn't do this just because she had a green light to do so, as it was something she would have to live with for the rest of her life.

And he advised her to consider the views of those in her community, many of whom were likely to oppose termination. "To overcome that, on a personal level, that's a great challenge as well," he said.

Ruba decided she would not want to terminate a pregnancy.

So when she got pregnant with her third child, Inara, in 2015, she refused the medical scans she was offered and turned down repeated requests from doctors to be screened.

"I wanted them to treat it like a normal pregnancy. I didn't want them to put the doubt in my head. I wasn't going to have an abortion, so I wanted to enjoy the pregnancy," she says.

"I used to say my husband there could be a chance this baby is ill as well, but he said, 'It's fine.' I think I had a lot of doubt - I knew the odds were the same as for the other two."

But Inara too was born with I-cell disorder.

"I was really happy that I had a baby, but when we saw her we kind of knew," says Ruba. "I was sad and upset that we went through all the pregnancy and we really wanted a healthy baby. I didn't know how much pain she would go through - but my husband was happy. He said, 'Just be grateful.'"

Inara died almost exactly a year ago, at the age of two. She fell ill with a chest infection last December and her condition deteriorated quickly. She was taken from the Bradford Royal Infirmary to York.

My husband says: 'If God is going to give me kids, then he can give me them from you... I'm not going to get married again'
"The doctors in York were trying to do 100% to keep her alive, I did have that hope but I could see she was in pain. She was sedated until she passed away. I had her in my arms for most of the time, then I lay down beside her. My husband realised she was taking her last breaths."

Ruba says she has no idea how they have all endured the pain of losing three children and of suffering six miscarriages, the last just weeks after Inara's death. "I didn't even know I was pregnant at that time and I miscarried after the funeral," she says.

She says it was Inara's death that made her accept a link between her children's misfortunes and cousin marriage.

For a long time she just did not believe it, in part because she saw other ill and disabled children at the hospice and it was clear that not all of them were conceived by married cousins. Some were from the white community.

"My husband still doesn't believe it," she says. "I believe it now because it's happened three times, so there must be something in what they're saying. It must be true."

After Inara's death, some of Ruba and Saqib's relatives, both in the UK and in Pakistan, came to the conclusion that they were unlikely to have a healthy child - and argued that the marriage should therefore end in a "happy separation". This would allow both partners to remarry and have healthy children with someone else.

"We both said no," Ruba says.

"My husband says: 'If God is going to give me kids, then he can give me them from you. He's given me kids from you and he can give me healthy kids from you. If it's written, it's written for you. I'm not going to get married again and neither can you get married again, we are both going to try together.'"

And although Ruba was reluctant to marry in 2007, after 10 years of married life she doesn't want to part.

"Relatives wanted us to be happily separated for the kids, so that I can have healthy kids with someone else and so could he. But what if I do have healthy kids with someone, they might not make me feel like he makes me feel? I might have kids but not a happy marriage. It might not be successful marriage, and I don't want to bring kids up as a single parent. I have heard about people doing this but it's not for us."

But what options does this leave them?

One possibility is to have IVF. This would enable doctors to screen embryos, rejecting those with I-cell disease, and selecting a healthy embryo to implant in Ruba's womb.

Saqib is not enthusiastic about this, Ruba says.

I thought the first time, when Hassam was diagnosed, that I couldn't do this - but I've done it three times
"He just says that whatever Allah is going to give us is meant to be - if we're destined to have a child like this then we can have it in any circumstances," she says.

For her part, Ruba would like to try IVF - but the length of the waiting list is a drawback.

"I want it to happen quickly. If you wait for something for a long time then it's more tempting to try naturally," she says.

Her husband has been to appointments with her but it's hard for him to take time off from the bakery where he works and he doesn't speak much English.

"He sits there not knowing what they're saying," she says. "He isn't keen, but says it's up to me."

Ruba says she cannot predict what will happen, but is concerned about what any naturally conceived child may have to endure.

"I thought the first time, when Hassam was diagnosed, that I couldn't do this, but I've done it three times so I'm not sure," she says. "But it isn't fair for the child to go through so much pain."

The couple's experiences have led others in the family, including Ruba's brother, to reject cousin marriage.

"We never use to think about the risks - up to my children we've never thought it was wrong to marry in the family, but because I've been through it my other relatives do think twice about going in the family," Ruba says.

"Ten years ago I just accepted what my parents said, but now our cousins have been given a choice and they're saying no to that. Our younger generation have been given a choice and if they don't like it they can speak up about it."

As well as losing three children, Ruba has also suffered six miscarriages, the last just weeks after Inara's death. She hadn't realised she was pregnant at the time, but miscarried after the funeral, when Inara was buried alongside her brother and sister.

She is sustained by her religion and supported by her parents.

"God only burdens a person with how much they can take. Sometimes I think people are so lucky, they don't have to try hard and they get a healthy child, but sometimes those children bring trouble when grow up and so those tests placed on them are different," Ruba says.

"In this life I'm the unluckiest person, but in the next life I will be the luckiest because they were innocent children. And those children help you in the next life, because you will be with them."