上帝叫圣父，耶稣叫圣子，还有圣母

son of god

孔夫子叫圣人而不叫圣子。不要乱说。“圣子”中的“子”是“儿子”的意思，指上帝的儿子，一般基督教把耶稣叫“圣子”

Without context, I'd say it may be a reference to the Son of God in the Bible. 聖 itself is tacked to the front of many people or things that suggests "absolute/ultimate/most high etc". You have Confucius (as Bruce mentioned), or any other person that has attained the pinnacle of literary and moral excellence (聖人). Or used as a description for imperial power (like 聖上，二聖臨朝). Or Christmas even (聖誕). Now you know what 聖 means, you can go ahead and add 子 and come up with your conclusion~

Maybe it's the typo of 蛏（cheng2）子, which is a kind of bar shaped clam.