fɹˈɛdɚɹˌɪk kɹˈɪstʃən ɹˌoʊmən tˈuː wʌz bˈɔːɹn ðɪ ˈɛldɪst sˈʌn ʌv fɹˈɛdɚɹˌɪk kɹˈɪstʃən ˈaɪ, dˈuːk ʌv ʃlˈɛswɪɡhˈɑːlstaɪnsˈɑːndɚbˌɜːɡˈɔːɡəsʔˌn̩bɜːɡ wˈʌn θˈaʊzənd sˈɛvənhˈʌndɹɪd twˈɛnti wˈʌn wˈʌn θˈaʊzənd sˈɛvənhˈʌndɹɪd nˈaɪnti fˈoːɹ, baɪ hɪz wˈaɪf ænd kˈʌzən pɹˈɪnsɛs ʃˈɑːɹlət ʌv ʃlˈɛswɪɡhˈɑːlstaɪnsˈɑːndɚbˌɜːɡplˈɜːn wˈʌn θˈaʊzənd sˈɛvənhˈʌndɹɪd fˈoːɹɾi fˈoːɹ wˈʌn θˈaʊzənd sˈɛvənhˈʌndɹɪd sˈɛvənti.
Frederick Christian II was born the eldest son of Frederick Christian I, Duke of Schleswig-Holstein-Sonderburg-Augustenburg (1721–1794), by his wife and cousin Princess Charlotte of Schleswig-Holstein-Sonderburg-Plön (1744–1770).