Can my son claim his child? My son had a relationship with a married woman who was separated from her husband. She is pregnant by my son, but has reconciled with her husband. The husband plans to claim the child as his own. Does my son have any recourse?

Yes.  Once the child is born, he can bring a paternity action to determine paternity of the child.  If the husband does in fact claim the child as his own and hold it out as such, then your son must bring his action no later than 2 years from the date of birth.  If the husband and wife stay together for two years and he holds the child out as his own, then after two years the statute of limitation bars your son's claim.  If the mother denies your son's paternity your son can demand DNA testing.  He  will most likely have to pay for it, but the court can order the mother to pay him back if the test proves him correct.  The court can also establish custody, visitation and child support as part of the proceeding