Titles like Khan, Syed, Sheikh, and Mirza are historically lineage-based or honorific surnames rather than religious requirements. ‘Syed’ traditionally denotes descent from the family of the Prophet Muhammad (peace be upon him) through his grandsons Hasan or Hussain; ‘Sheikh’ often indicates scholarly lineage or, in South Asia, descent from early Arab or Sufi settlers; and ‘Khan’ is a title of Central Asian and Mongol-Turkic origin later adopted widely across Muslim South Asia, unrelated to Arabian lineage. Using any of these as a surname is culturally established and Islamically permissible, and does not affect the religious validity of the child’s given first name — the two are simply independent parts of a full name serving different purposes (identity of person vs. identity of lineage/family).