Not likely but absolutely possible for your offsprings to have some defect. With each successive cousin marriage the chance is greater. However little chance there is, the gravity of disease is severe enough to deter most people. I mean its not like 1 apple with a problem among a total of 2,3,4,5 or whatever, so that you just get another. A single person is extremely important, and a single capability/feature of a person is important.(In non-cousin marriages, there is also a chance but usually extremely minute compared to this). If parents of you both, and the parents of your parents and so on, have been marrying outside the family, it is highly likely any problem you can have in your(you and your proposed mate) genes, would not have appeared since it was masked. So, in family history, you might not find any abnormality which could have been carried on, hidden. If that particular thing is common to both of you, there is some chance it would appear. However, you can also do tests at particular time of child's growth inside the mother, to see for some of the normally known problems. But this situation is also quite odd, deciding whether you would continue the pregnancy or stop. So, its an odd situation but it is always unpredictable in any(cousin and unrelated, although less so in latter) case so....... idk