pass the selected value of Html.DropDownList to controller

Question

I have a drop down in my view page. Since the drop down has only two values and it will not change so we decided to create static drop down.

@Html.DropDownList("RelationshipWithFather", new List<SelectListItem>()
 {
   new SelectListItem() { Text= "son", Value = "son" },
   new SelectListItem() { Text= "daughter", Value = "daughter" }
 }, "relationship...", new { @class = "form-control" })

How to pass the selected value of this RelationshipWithFather drop down to create controller method.

public ActionResult Create(PatientInfo vdm_)
        {
            if (ModelState.IsValid)
            {
                PatientInfo vdm = new PatientInfo();
                vdm.relationshipWithPatient = // selected value of RelationshipWithFather
            
            
            }
        }

I have to set the value of the selected dropdown to the relationshipWithPatient attribute of the model class.