i just read this

A crucial event that determines whether the embryo will develop into a male or female occurs in the second half of week six.
At only 40 days after fertilization electrical waves as measured by the EEG can be recorded from the baby's brain, indicating brain functioning
Forty-nine days after conception, magic happens. It is on this 49th day when we sexually diversify (becoming either male or female).
scientists say that a person's pineal gland is fully formed 49 days after conception as well.
The human pineal gland becomes visible in the developing fetus at seven weeks, or 49 days, after conception.
Of great interest to me was finding out that this is nearly exactly the moment in which one can clearly see the first indication of male or female gender. Before this time, the sex of the fetus is indeterminate, or unknown.
Until the fetus is 40 days old, it is still called a "drop" since it is indeterminate whether it will be a boy or girl.
When the drop of (semen) remains in the womb for forty or fifty (days) or forty nights, the angel comes and says: My Lord, will he be good or evil? And both these things would be written. Then the angel says: My Lord, would he be male or female? And both these things are written. And his deeds and actions, his death, his livelihood; these are also recorded. Then his document of destiny is rolled and there is no, addition to and subtraction from it.
The Gemaruh states that just like the Torah was given in 40 days, so too the Neshama is created in 40 days ( " Neshama Nozrah " ). The Gemarauh in Niddah 16B talks about, at the time of conception ( 40 days before the fetus takes shape ), that an Angel takes a drop from conception, and brings it too Hashem, and it is at that moment in time that it is decided who he is going to marry, rich, house, etc
the Tibetan Book of the Dead, says that the soul enters the fetus 49 days after conception. Interestingly, this is exactly when internal sex organs are fully developed and the pineal gland is formed (some people believe the pineal gland is the seat of the soul). There are also passages in the Bible that can be interpreted to support the 49 days after conception notion
the Tibetan Buddhist Book of the Dead teaches that it takes forty-nine days for the soul of the recently dead to "reincarnate." That is, seven weeks from the time of death of one person elapses until the life-force's "rebirth" into its next body. It takes forty-nine days from conception for the first signs of the human pineal to appear. Forty-nine days is also when the fetus differentiates into male or female gender. Thus the soul's rebirth, the pineal, and the sexual organs all require forty-nine days before they manifest.
In Indonesia, 40 days is referred to as the period it takes for the soul to complete its wandering in the borderland between the physical and higher worlds before settling in its destined home in the subtle spheres.
According to the Talmud, the soul enters the body on the 40th day after conception.

Daniel 9:25-27, 'Know therefore and understand, that from the going forth of the commandment to restore and to build Jerusalem unto the Messiah the Prince shall be seven weeks.
Pentecost is 49-days after Easter and Pentecost is the day when the elders in the temple were surprised by a gusting wind when suddenly tongues of fire came down and rested upon their heads. In other words, their crown chakra was illuminated, the pineal gland was functioning, and the spirit came down onto man. This is obviously symbolic for forty-nine days after the literal conception, when the spirit literally descends down onto us and gives us our soul;