My wife and I are both carriers of the sickle-cell disease, should we take the risk of having kids or not?

Get counseling. The course of sickle cell anemia is variable; some do fairly well. There is a new medication called Hydroxyurea that lessens many problems, and there is excitment about gene therapy as a potential cure, it is possible by chorionic villous sampling (cvs) to detyermine by 8-10 week whether the fetus is affected; if so a mother can decide whether or not to continue the pregnancy.
Personal choice. During my training i encountered a man that couldn't face a 5% recurance risk he & his wife would have with another child after the first died with unexpected complications.That choice is personal. Ss disease is chronic, painful, unpredictable and can be devistating. Your basic risk is 25% with any pregnancy prenatal diagnosis is possible around 16 weeks but the procedure could end the pregnancy.