Yes, birthdates on June 17th, 1991 was pure yin.
Lunar calendar: June 17th, 1991
Gregorian calendar: Sunday, July 28th, 1991 Leo
Chinese character: Xin Wei? B not? Jihai? Yi hai?
yin and yang: yin and yang? Yin Yin? Yin Yin? Yinyin
information source: Hua. com.