Supporting Foster Youth in Successful Parenting Act of 2017 This bill amends part B (Child and Family Services) of title IV of the Social Security Act to require states to report to the Department of Health and Human Services (HHS) on steps taken to address pregnancy and parenthood among foster youth. HHS shall make grants to states to identify and implement approaches to support foster youth in successful parenting. The bill specifies that: (1) pregnancy and parenting are sufficient reasons to remain in foster care until age 21, (2) states must strive to keep parents with their children, and (3) children born to foster youth are not required to enter foster care. The Federal Interagency Work Group on Child Abuse and Neglect shall identify and address issues facing foster youth who are expectant or parenting. HHS is encouraged to promote the sharing of emerging lessons, research, and best practices about preventing teen pregnancy among foster youth, and enable foster youth who are parents to receive support from those working in the areas of teen pregnancy prevention and child welfare. State certifications under the John H. Chafee Foster Care Independence Program must ensure that each youth in the program who is expectant or parenting will receive independent and transition planning services that can support them in raising a child.