Conversation so far:
When was Recep Tayyip Erdoğan born?
26 February 1954
Where was Recep Erdoğan born?
Erdoğan was born in the Kasımpaşa neighborhood in Istanbul.
Who were Recep Tayyip Erdoğan's parents?
His parents were Ahmet (1905–88) and Tenzile Erdoğan (née Mutlu; 1924–2011).

Question: Who were his siblings?
Self-contained rewrite: Who were Recep Tayyip Erdoğan's siblings?