Genetic Compatibility - Is your Genotype and Blood group Compatible with the Person you're considering Marrying?

Genotype definition

Genotype...

simply refers to hemoglobin gene constituents. Genes are always in pairs and overall expression depends whether dominant, recessive or X-linked. So there is no problem when one of the genes is abnormal e.g. AS, AC. This is called a carrier state (sickle cell trait). Only when the two are abnormal then there is a great problem.

The genotypes in humans are AA, AS, AC, SS.
I hadn't heard of the genotype AC until I was researching for this article and found Dr. Peter's article (Dr. Ademola Peter) on the subject of genotypes and blood groups. He's also the one I quoted above and throughout this article.
Anyway, I guess AC is either not common in genotypes or not common in Nigerians. But AS and AC are both abnormal take note.
And the great problem referred to above that we're trying to avoid with genotype matchmaking for intending couples is the Sickle cell disease.
Sickle cell disease (a recessive disorder) is a very serious medical condition with high prevalence rate in sub Saharan Africa. Intending couples must make sure to know their genotypes and be sure it's compatible for marriage before going ahead to get married.
So who can you marry and who shouldn't you marry based on Genotype compatibility?
Someone with the genotype AA can marry across. That is there's no risk of having a sicklier for a child even when he or she marries an SS. But AA marrying an SS can only result in AS children. There's no hope of having a child with the genotype AA. But there's no danger either.
Someone with the genotype AS should only marry someone with the genotype AA because if AS marries AS there's one out of 4 chances (AS, AS, AA and SS) that they will have a child with the sickle cell disease. Same applies when AC is combined. AC and AS combine will produce AA, AS, AC, SC, the sickle cell disease will be SC. Remember what the quote above from Dr. Peter said, it's only when two abnormal marry that there is a great problem.
Of course there are many cases where two abnormal was combined that is an AS and AS or AC and AC or AC and AS couples and had up to five or six children without a single sicklier among them. But why risk it? What if you're not so lucky? Can you forgive yourself when you end up having a child with the sickle cell disease and put the child through the agony the disease brings when you could have easily avoided it?
Compatible genotypes for marriage are:
AA marries an AA. That's the best compatible. That way you save your future children from having to worry about genotype compatibility in future.
AA marries an AS. You'll end up with kids with AA and AS which is good. But sometimes if you're not lucky all the kids will be AS. Like my elder sister who is AA and married an AS and was expecting to have kids with genotype mostly AA. But the last I heard two out of her 3 kids are AS; I'm not sure what the genotype of her third child is. Like I've said there's no problem having kids with AS except if eventually the kids marry people with the genotype AS.
AS and AS should not marry.
AS and SS shouldn't think of marrying.
And definitely SS and SS must not marry since there's absolutely no chance of escaping having a child with the sickle cell disease.