Yes, two O-positive couples can absolutely have a baby.
Understanding Blood Types and the Rh Factor
Blood type is determined by genes inherited from both parents. The ABO system categorizes blood into types A, B, AB, and O. The Rh factor is a separate protein; if present, the blood type is positive (+), and if absent, it's negative (-).
-
O blood type: Individuals with O blood type have two recessive O alleles. Therefore, parents with O blood type will always pass on the O allele to their offspring. As stated in the reference from Byju's, "The progeny formed if both parents are of O blood group is O". (https://byjus.com/question-answer/what-is-my-blood-type-if-both-parents-are-o-positive/)
-
Rh factor: The Rh factor is inherited separately. A person can be homozygous (++) or heterozygous (+-) for the Rh-positive trait. Two Rh-positive parents can have a child with Rh-negative blood if both parents are heterozygous (+-). However, an O+ couple can have a child with O+ blood type.
-
O+ Parents and Offspring: If both parents are O+, their child will inherit an O allele from each parent, resulting in an O blood type. The child could inherit either ++ or +- for the Rh factor, resulting in an O+ blood type. As stated in several references, there is no risk in this case. (https://www.icliniq.com/qa/blood-typing/me-and-my-fiance-have-same-blood-group-will-it-affect-our-baby)
Conclusion
Two O-positive parents can have a child. The child will inherit the O blood type and the Rh factor will be determined by the specific Rh alleles inherited from each parent. There's no inherent incompatibility that would prevent conception or a healthy pregnancy.
