We celebrate his birth as a solemnity on June 24th. Note that we celebrate most saints on the day their died. The only birthdays we celebrate are for Jesus, Mary and John the Baptist because these three are the only ones born without original sin.
I am not sure that it is dogma that John was born without original sin, but it is a strong tradition that he was cleansed of original sin on the occasion of Mary’s visit to Elizabeth, and that is why he leapt in Elizabeth’s womb.
43 And why is this granted me, that the mother of my Lord should come to me? 44 For behold, when the voice of your greeting came to my ears, the babe in my womb leaped for joy.
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