Mike,
Do you know what the Arabic word that is used that expressed that ?
When the Holy Spirit is mentioned in the Quran is the word "Holy" equivalent to "Holy" in " a holy son" ?
In the Quran the Arabic for "Holy Spirit" is Roohul-Qudus.
Rooh = Spirit ......Qudus = holy
Now what does the Quran say in the Arabic as to the son of Mayam in 19:19 ?
"a holy son" is from the Arabic "ghulaaman zakeeyaa"
ghulaaman = a child, a boy........zakeeyaaa = purify, clean, holy
Two different words "Qudus vs Zakeeyaa" have absolutely two different significance from what English conveys.
The word Zakeeyaa is the same word in significance that we use for Zakaah which is the muslim's alms tax that we have to pay out of our wealth.