'Excruciating pain'

SCD is the world's most common hereditary blood disorder, and many people who are interested in having children, like Ogunnupebi, emphasize genotype testing to avoid giving birth to children with the disease.

Strokes, paralysis, and leg ulcers are also frequent complications.

Osayi Olotu, a social entrepreneur from Nigeria who battled sickle cell, says the episodes of pain that come with the illness are extremely painful, and can sometimes get out of control very quickly.

"There is no way to describe the pain. It is excruciating, it feels like pressure on your bones. Like someone is trying to break all of your bones at the same time," he told CNN.

Sickle cell disease, which is also called SS genotype, is an inherited form of anemia -- a condition in which there aren't enough healthy red blood cells to carry adequate oxygen throughout the body, says Dr. Zainab Jimoh-Johnson.

For a child to be born with the condition, both parents must carry a sickle-cell gene, (known medically as AS genotype), which is passed from one generation to the next. If someone with a trait marries another person with it, there's a higher chance that their child will be born with the disease.

Jimoh-Johnson says carriers of the trait are advised to marry non-carriers who have the AA genotype.

'I don't want to be a young widow'

"Generally, people who know their genotype from an early age or before getting into a serious relationship are able to make informed decisions before feelings or relationships are formed," Sanusi told CNN.

Authorities in Nigeria have also stepped in to prevent couples from getting married if they carry sickle cell traits.

The bill states that no religious body or registry should join couples together without presenting a particular certificate.

Ogunnupebi, 28, says she went through a series of painful breakups over genotype compatibility issues.

"I had a wonderful boyfriend in 2014, but that relationship painfully ended because we both have the AS genotype. We didn't want to put our children through frequent sickle cell crisis," she said.

Nigerians in the dating scene sometimes discriminate against those with sickle cell disease, Olotu says.

"Before my transplant, there were a lot of cases where girls didn't want to date me because I had sickle cell. There are people with the AA genotype who are compatible with others but don't want to date those with sickle cell," he told CNN.

"In 2013, there was this particular girl I wanted to go out with, she told me she wasn't interested because she didn't want to be a young widow. I felt like she was telling me my life on earth would not be as long as hers," he added.

'It's a black man thing'

Olotu, 34, says conversations about genotypes are almost nonexistent in other parts of the world.

"Sickle cell is a black man thing. I lived in Newcastle, a predominantly white town in England, and I had to explain what SCD was and how to pre-treat me. My friends didn't even know what it was," he said.

No known cure

O
lotu had a transplant at the National Institute of Health in the United States in 2017 and he says he is now free of the disease.

"You have to find a donor that matches you, which takes a while," he said describing the process. "Then you start with chemotherapy. I did chemo for five days before going ahead with the transplant," he added.

Although Olotu no longer experiences sickle cell complications, if he wants children in the future, he has to ensure a match with someone with the AA genotype to avoid having children with the disease.

He believes that Nigerians who don't have sickle cell traits should be encouraged to consider dating those who have it to prevent discrimination.

"The 'who you date,' conversation should also center around marrying or dating those with sickle cell. If you're AA you should go for someone with the SS genotype," he says.