Some additional thought:
Birthday form a Buddhist view, the day of birth is not really the day one leaves the mother womb. Birth, rebrith takes place with the conception. "Curiosly" in some SEAsian countries, the counting of ages starts with one. So people if you ask, would be one year older then if you count the years from the day of birth form a western view. A new born, if asking is one year old.
The brithday (leaving the physical connection with the mother) would be somehow an excellent day to pay respect and gratitude to once mother and maybe to thanks for all the generisity that was received till this day. So it would be maybe a perfect day to honor mother father an all supporters and friends.
In regard of the worship day of the preceptor, I guess that is simply a confusion. The honoring day of the preceptor, as far as I know, has long tradition. I guess it is simply mixed up with new and strange trends.
Birthday celerbration is also something new in western culture and had never this kind of dimensions (atta/jati/conceit...).
Some views to religions (
wiki):
Judaism
In Judaism, the perspective on birthday celebrations is disputed by various rabbis.[15] In the Hebrew Bible, the one single mention of a celebration being held in commemoration of someone's day of birth is for the Egyptian Pharaoh which is recorded in Genesis 40:20.[16] Rabbi Moshe Feinstein always acknowledged birthdays.[17] The Lubavitcher Rebbe actually launched a campaign to encourage people to celebrate their birthdays, by gathering friends, making positive resolutions, and through various religious observances.[18] According to Rabbi Yissocher Frand, a person's birthday is a special day for that person's prayers to be accepted.[19]
The bar mitzvah of 13-year-old Jewish boys, or bat mitzvah for 12-year-old Jewish girls, is perhaps the only Jewish celebration undertaken in what is often perceived to be in coalition with a birthday. However, the essence of a bar/bat mitzvah celebration is entirely religious in origin (i.e. the attainment of religious maturity according to Jewish law) and not secular, despite modern celebrations where the secular "birthday" element often overshadows the essence of it as a religious rite. With or without the "birthday" celebration, the child nevertheless becomes a bar or bat mitzvah, and the celebration can be on that day or any date after it.
Christianity
Christianity: Early centuries
The early Christians did not celebrate Christ's birth because they considered the celebration of anyone's birth to be a pagan custom.[citation needed] For example Origen in his commentary "On Levites" writes that Christians should not only refrain from celebrating their birthdays, but should look on them with disgust.[20]
Orthodox Christianity still prefers the celebration of name days only.
Christianity: Medieval
Ordinary folk celebrated their saint's day (the saint they were named after), but nobility celebrated birthdays. The "Squire's Tale," one of Chaucer's Canterbury Tales, opens as King Cambuskan proclaims a feast to celebrate his birthday.[21]
Christianity: Modern
Jehovah's Witnesses and some Sacred Name groups refrain from celebrating birthdays, as did the early Christians of Christs era, on the basis that they are portrayed in a negative light in the Bible and have historical connections with magic, superstitions, and Paganism.[22][23][24][25][26]
Islam
Some clerics consider the celebration of a birthday to be a sin, as it is considered an "innovation" of the faith, or bi'dah while other clerics have issued statements saying that the celebration of a birthday is permissible.[27][28]
Some Muslims (and Arabian Christians) migrating to the United States adopt the custom of celebrating birthdays, especially for children, but others resist.[29]
There is also a great deal of controversy regarding celebrating Milad-ul-Nabi - the birth anniversary of Muhammad. While a section of Islam strongly favours it,[30] others decry such celebrations, terming them as out of the scope of Islam.[31]
Hindus
Hindus celebrate the birth anniversary day every year when the day that corresponds to lunar month or solar month (Sun Signs Nirayana System – Sourava Mana Masa) of birth and has the same asterism (Star / Nakshatra) as that of the date of birth. That age is reckoned whenever Janma Nakshatra of the same month passes.
Only the romans enthusiastically celebrated birthdays with hedonistic parties and generous presents, as far as my reseaches reaches. But even the Gaul use to say:
These romans are crazy! But after a while...

Some wage but interessting researches about the origin:
Happy birthday