Dr. Stevens does the DNA test to determine whether or not Javier is the father of Zoila's unborn child. He eventually calls her back, revealing that he is in fact not, thus meaning it's Pablo. He is first mentioned in "Awakenings".
Four months after learning she is pregnant, Zoila finally decides it's time to run a DNA test, thus revealing who the father of her child really is - Pablo or Javier. With the help of Genevieve, Zoila manages to take ten of Javier's hairs, and sends them in for the test. She later receives a call back from Dr. Stevens, revealing Javier is not the father, thus meaning that it's Pablo. ("Awakenings")