Uniting Families Act of 2017 This bill amends the Immigration and Nationality Act to establish a non-immigrant W-visa category for an alien who: (1) is 18 or older and is the genetic son or daughter of a U.S. citizen who served in the Armed Forces on active duty abroad, or (2) is the spouse or child of such alien and is accompanying, or following to join, such alien. A visa shall not be issued until a petition has been filed in the United States by the applicant's citizen parent and approved by the Department of Homeland Security (DHS). Such petition shall include: DNA evidence establishing that the alien is the petitioner's genetic child, a written agreement that the parent will provide financial support until the alien's status is adjusted to lawful permanent resident status, and information establishing that the petitioner is a U.S. citizen who served in the Armed Forces on active duty abroad. The bill provides that: (1) the period of authorized admission for a W-visa alien is five years, which may be extended for one additional two-year period; and (2) the total number of principal W-visa aliens who may be admitted during any fiscal is 5,000. The bill prescribes the criteria that a W-visa alien must meet in order to adjust to lawful permanent resident status, including an understanding of the English language and U.S. history. (Such language and history requirements for naturalization purposes shall not apply to a person who has satisfied them in adjusting from W-visa status to lawful permanent resident status.)