This is another confusing question that if initially taken in its literal sense, the practicality would be far impossible. If taken in the nature of an English Idiom, these groups of words or phrases would actually mean anyone being wealthy or rich since birth. The expression of “being born with a silver spoon in the mouth” is oftentimes used for persons with wealthy family backgrounds of someone who is economically stable, so to speak.
The idea of silver spoon as an adjective to describe the abundance of wealth that one possesses came as silver spoons in particular are very precious and considered expensive during those times. It is believed these treasures are the most priced among the kitchen utensils. There were also times that these silver spoons were listed as number one targets of burglars. Being wealthy during those times coincided with the rich family’s healthy backgrounds as well. The rich children being fed through these silver spoons were believed to acquire fewer illnesses as compared to the normal ones that are fed through other metal spoons. The wealthy ones during those times enjoyed the silver spoon’s antibacterial effects.
Thus, a child or anyone to have been said to be born with a silver spoon in his mouth is definitely a wealthy and a lucky person considering that he will not exert all his efforts to be one for it is already given to him since the day he was born. Even if the person is not worthy of it himself, it would also imply that he has a very wealthy and prosperous family background as well. The best examples of which are those people belonging to the royal family or the descendants of kings and queens. But if we are to literalize its meaning, it maybe possible that the person’s mom that you are referring to might accidentally swallowed a silver spoon while conceiving! (the swallowing part is less convincing, by the way…)