Depends on partner
Sickle cell disease
requires that the s gene be passed to a baby during conception from both parents.
In theory, someone with sickle cell disease could only pass one gene, so if the partner had normal hemaglobin genes, the baby would have trait, not ss. If the partner had trait, both trait or ss is possible. If both parents have sickle cell ss disease, all their babies would have sickle cell.