There is a special word with different spelling variations that are all similar but have different meanings
One such variation is monogenes
One of the variations means a One and Only Unique thing and does not necessarily mean a biological son
Jesus is called the Only begotten in some translations of John 3:16 but called the one and only in other translations
If he is born of a virgin who is not a god and has no biological father then unique makes more sense than begotten