Userform Validation - combining code?

Userform is adding info for up to 20 people (Potential for 8 adults labeled Adult1, adult2..... and 12 children labeled Child1, child 2....)

for each of the people, I have to run the same validations.

1. If a first name is entered there MUST be a last name entered
2. If a last name is entered there MUST be a first name entered
3. If a first name and last name is entered a DOB must be entered
4. If a first name and last name is entered then a validation yes/no box is to be checked.

I am basically looking to try and combine the macro code behind the scenes in an effort to optimize.

Example of DOB Validation code is

is there any way to do this?

Private Sub TextBox14_Exit(ByVal Cancel As MSForms.ReturnBoolean)
    If DisableEvents Then Exit Sub

       If Me.TextBox12.Value <> "" Or Me.TextBox13.Value <> "" Then
 
            If Not TextBox14.Value Like "##[/]##[/]####" Then
                MsgBox "Adult 1 DOB Must Be in the Format of mm/dd/yyyy"
                       Cancel = True
                       TextBox14.Value = ""
            Else

            If DateValue(TextBox14.Value) > DateValue(Now) Then
                MsgBox "Adult 1 DOB Must be in the Past"
                       Cancel = True
                       TextBox14.Value = ""
        
            Else
                       TextBox14.SetFocus
            End If
        End If
    End If
End Sub