In In re Zacharia D. (1993) 6 Cal.4th 435. the California Supreme Court evaluated an unwed, biological father's right to reunification services and custody of a child who had been made a dependent of the court. (In re Zacharia D., supra, 6 Cal.4th at pp. 439, 445.) In Zacharia D., the birth mother named her live-in boyfriend as the father on the birth certificate; however, nine months prior to the child's birth, the mother had a two-week sexual relationship with the man who ultimately was determined to be the biological father. (Id. at p. 439.) A dependency petition was filed on behalf of the child shortly after his birth, but the biological father did not learn about the child's existence until some 15 months later. (Id. at pp. 439-440.) After learning about the child, the biological father asked to see pictures of the child, suspected that the child might be his, and then met the child. (Id. at p. 440, and fn. 2.) However, he was unsure he was the father, and he did not attempt to establish a relationship with the child, did not indicate any willingness to support him, and did not communicate with the dependency agency or court. (Id. at p. 440.) About four months after learning about the child's existence (by which time the child was 19 months old and the 18-month review hearing was being conducted), the biological father finally communicated with the court to request a paternity test. (Id. at pp. 440-441.) However, the biological father still did not request visitation or make any effort to communicate with or inquire about the child's needs. (Id. at pp. 442-443.) The juvenile court ultimately terminated the biological father's parental rights without providing him reunification services, reasoning that he delayed too long in pursuing his parental rights-i.e., failing to inquire about pregnancy after having sexual relations with a woman and failing to promptly assert his rights once he suspected he could be the father. (Id. at pp. 443-444, and fn. 8.) In upholding the juvenile court's ruling denying the father reunification services, the Supreme Court in Zacharia D. concluded that the biological father had not achieved Kelsey S. status; that is, the father had not claimed he was precluded from attaining presumed father status by the mother or any third party, and he had not demonstrated a timely commitment to parent the child. (In re Zacharia D., supra, 6 Cal.4th at p. 451.) The Zacharia D. court held that the biological father had no right to extend the reunification period merely because of his "own failure to ascertain the existence of his child, or by his decision to wait until the 18-month hearing to assert his paternity claim." (Id. at p. 452.) The court noted that there was no evidence the mother hid her pregnancy or the child from the biological father, and the biological father's ignorance of the child's existence arose from his own indifference after his sexual encounter with the mother. (Ibid.) The court concluded that "if a man fails to achieve presumed father status prior to the expiration of any reunification period in a dependency case, whether that period be 6, 12, or 18 months as in this case, he is not entitled to reunification services." (Id. at p. 453.) The court's rationale focused on the need for the father to timely assert his rights and responsibilities as a parent: "While under normal circumstances a father may wait months or years before inquiring into the existence of any children that may have resulted from his sexual encounters with a woman, a child in the dependency system requires a more time-critical response. Once a child is placed in that system, the father's failure to ascertain the child's existence and develop a parental relationship with that child must necessarily occur at the risk of ultimately losing any 'opportunity to develop that biological connection into a full and enduring relationship.'" (Id. at p. 452.)