Every time a couple has sex, they should be open to life. The baby is always a potential. Ending a life when you know that you have already created one and chose to create it is cruel and unjust.
If the parents cannot support the child when it is born, it is better to know that your child can have a life with another family, than to know that you aborted him, which in my oppinion is killing him.
If the baby is theirs then why would you abort it? Adoption is not easy, but abortion is even harder in my opinion. Studies show that abortion tramatize the woman and makes it harder to her to emotionally bond with any future children she might have.