In Kiddushin mishnayos 4:2, it says:
And which are the shetukim? Anyone who knows [who] his mother [is], but does not know [who] his father [is]. And which are the asufim? Anyone who was gathered in from the market, and does not know [who] either his father or his mother [is]. Abba Shaul would call the shetukei, "investigated ones."
If someone never physically met their father, but has various information about him, such as his last name, possibly full name, his profession, his brother's profession etc., are they a shituk? (It is also known he, the father, is Jewish)