[Drammach]

One of the concepts of asrology is not only the positions of the Stars ( planets, signs of the zodiac ) but also the location of the subject..

While the astrologers ( or "wise men" ) may have calculated the time and place deemed "most auspicious" for the arrival or birth of a VIP, possibly to be interpreted as the Messiah, all of their calculations would not necessarilly tell them WHO that person was..
Only Where and When..

It then comes down to how many children were born in Bethlehem on that day/night when conditions were best..
How many were actually MALE..
How many male children actually survived the executions tradition says Herod ordered..
Lastly, how many male children fulfilling all the aforementioned prerequisites, and additionally, fullfilling all the other requirements listed by the prophets ( lineage, etc..) as well..

A remarkable set of "circumstances".. ( I won't say coincidence ) ..

[NYer]

It then comes down to how many children were born in Bethlehem on that day/night when conditions were best..

King Herod believed the 3 Magi and wasted no time executing all of the male children, 2 years and under.

Giotto di Bondone
No. 21 Scenes from the Life of Christ
Massacre of the Innocents
1304-06 -- Fresco
Cappella Scrovegni (Arena Chapel), Padua 

Gospel - Matthew 2:13-18

Now when they had departed, behold, an angel of the Lord appeared to Joseph in a dream and said, "Rise, take the Child and His mother, and flee to Egypt, and remain there till I tell you: for Herod is about to search for the Child, to destroy Him." And he rose and took the Child and His mother by night, and departed to Egypt, and remained there until the death of Herod. This was to fulfill what the Lord had spoken by the prophet, "Out of Egypt have I called My Son."

Then Herod, when he saw that he had been tricked by the wise men, was in a furious rage, and he sent and killed all the male children in Bethlehem and in all that region who were two years old or under, according to the time which he had ascertained from the wise men. Then was fulfilled what was spoken by the prophet Jeremiah:

"A voice was heard in Ramah, wailing and loud lamentation:
Rachel weeping for her children;
she refused to be consoled because they were no more."