The Priesthood was for Israel only at that time.  They were chosen by God of the tribe of Levi. It was never for Gentiles than or now. The purpose of the priesthood was to do service to God! Today we frequently hear the admonition for the man to assume his proper place as priest of his home. This means he is the spiritual leader, the mediator between God and his wife and children. As the supposed mediator, God would speak to wife and children through him, and work through him on their behalf. As priest, he is the governing ruler who makes all final decisions about everything. As priest and head of the house, he must act with authority, to insure obedience to those decisions.

Where did this doctrine come from? Is it biblical?

The "man is the priest of the home" cult refers to a few Old Testament verses to prove the priesthood of man existed the before the Law was given to Moses, as a basis for their theory. Gen.8:20 "...and Noah builded an alter unto the Lord and offered burnt offerings on the alter."
Gen.26:25 "...and he (Isaac) builded an alter there and called upon the name of the Lord and pitched his tent there, and there Isaac's servant digged a well."
Gen. 31:54 "...Then Jacob offered sacrifice upon the mount and called his brethren to eat bread and they did eat bread and tarried all night in the mount."
Those verses CANNOT be construed to mean that every man was a priest in his home.

O.T. definition of Priest: Strong's # 3547, prim. rt. apparently meaning to mediate in religious service; but used only as a denomnative (derived from). from # 3548: to officiate as a priest; fig. to put on regalia, deck, be (do the office of a, execute the, minister in the) priest's office. # 3548: act. part, of # 3547, lit. one officiating, a priest, also (by courtesy) an acting priest (although a laymen), chief ruler, priest, prince, principal officer. Some people appropriate these definitions as proof that males are the priests of their homes. However, home was not a place where animal sacrifices were made. It was forbidden for anyone to make those kind of sacrifices except the official, God appointed, priests. These were done ceremonially, at specific times and places and in a specific way. The priests officiated in an earthly sanctuary or tabernacle made by man. Some were allowed into the first section. There was a veil dividing the sanctuary and only the High Priest was allowed to go behind that veil once a year.

All scripture that deals with O.T. priests of God specifically speaks of only certain men who were called and anointed by God to act as mediators and intercessors for all people, including men.  People, who were not called and appointed by God, but who acted like priests on behalf of themselves or others, were slain.

EX.19:20-24 Certain people were called priests, but only Aaron and Moses were allowed to go near to God. Those who were called priests were not sanctified to go near God and would be killed if they presumed to do so. NUM.3:10 "and thou shalt appoint Aaron and his sons, and they shall wait on their priest's office and the stranger that comes near shall be put to death."

NUM.16 is about Korah who presumed to move himself into the priesthood and he and all his people were killed by earthquake or fire from God.
NUM.18:7 "...I have given your priest's office as a service gift; and any stranger that cometh near shall be put to death.

II CHRON. 26:16-21 King Uzziah presumed to burn incense in the sanctuary like the priests did. He was told that he had trespassed against God and he was struck with leprosy which remained until he died. Should any man presume to take the place of priest over his household? The priesthood was a sacred, holy, calling of God for specific people. Only the priests had access to God and mediated for all other people. It was an office of service. They did not dominate the people. Rather, the purpose for them was that they alone were authorized by God to make sacrifices to God on behalf of the people.

EX. 19:5,6 "Now therefore, if you will obey my voice indeed, and keep my covenant, then ye shall be a peculiar treasure unto me above all people, for all the earth is mine,  And ye shall be unto me a Kingdom of priests, and an holy nation. These are the words which thou shalt speak unto the children of Israel."

This was a promise that IF they ALL obeyed his voice and kept his covenant they would ALL be priests, including the women. This did not mean that all would operate in the "office" of priest, because that office would no longer exist. Instead, each person would have access to God and act as their own priest. However, they did not keep his covenant, nor did they obey his voice. The covenant was an imperfect one and none could accomplish it. (Heb.9:1-10). That is why there was a better covenant with better promises made through Jesus Christ. (Heb.8:6-9,13)

New Testament Definition of priest—Strong's # 2409 from #2413 of uncert. affin., sacred, holy; # 749 & #2409, high priest (lit. of the Jews, typ. Christ) by extension chief priest, chief high priest, chief of the priests. #746-arche from # 756- (prob. abstr) a commencement of (concr) chief in various applications of order, time place, or rank, beginning, corner, (at the first estate) magistrate, power, principality, principle rule.

Males have appropriated the priesthood of the home for themselves, but based on this definition, they are appropriating the place of Jesus Christ himself. Today, the only high priest is Jesus Christ. Heb. 7,8,9 tells the whole story. Heb.7:11-19 "If, therefore, perfection were by the Levitical priesthood (for under it the people received the law), what further need was there that another priest should rise after the order of Melchizedek, and not be called after the order of Aaron? For the priesthood being changed, there is made of necessity a change also of the law. For of whom these things are spoken pertaineth to another tribe of which no man gave attendance at the alter. For it is evident that our Lord sprang out of Judah of which tribe Moses spoke nothing concerning the priesthood".

Jesus was born out of the tribe of Judah not the tribe of Levi from which all priests came.

"And it is yet far more evident; for after the similitude of Melchizedek there ariseth another priest Who is made not after the law of a carnal commandment but after the power of an endless life. For he testifieth, Thou art a priest forever after the order of Melchizedek.

For there is verily an annulling of the commandment going before fear the weakness and unprofitableness of it.

For the law made nothing perfect, but the bringing in of a better hope did, by which we draw to near unto God." 21 "(For those priests were made without an oath but this with an oath by him that said unto him 'The Lord swore and will not repent, Thou art a priest forever after the order of Melchizedek'), by so much was Jesus made a surety of a better covenant."

Vs. 23-those other priests all died.
Vs. 24-Because Jesus lives forever his priesthood is unchangeable.
Vs. 25-because of that, he ever lives to make intercession.
Vs.26-He is a fitting priest for us because he is holy, harmless, undefiled, separate from sinners, and higher than the heavens.
Vs.27-other priests had to go daily to offer up sacrifices for their own sins and for sins of the people. Jesus did this only once when he sacrificed himself.
Vs.28-the law made high priests who had weaknesses, but Jesus' priesthood was consecrated for evermore by an oath from God himself.

 How Jesus changed the priesthood

Heb.8:1 He sits at the right hand of God.
Vs.2 He is the minister of the sanctuary and true tabernacle that was pitched by God and not man. (Who are the living stones of living sanctuaries or holy temples now? He alone is the only High Priest that ministers to them.)
Vs.3-4 other priests were ordained to offer gifts and sacrifices according to the law.
Vs.5 the tabernacle was built after a specific pattern as a shadow of the things to come.
Vs.6 He obtained a more excellent ministry as a mediator of a better covenant established on better promises.
Vs.7 If the old covenant had been faultless, there would be no need of a second or new covenant.
Vs.8 The Lord found fault with Israel and so He said he would make a new covenant with them.
Vs.9 This new covenant would not be the same covenant He had made with the fathers because they did not continue in that covenant. So he regarded them not. Regarded, Strong's #272, be careless of, neglect, make light of, negligent. From (1) privation and (3199) of interest, care and concern.

Privation = the state of lack of something necessary or desirable, especially, want of common comforts of life. In other words he withdrew his interest, concern and care for them for the time being. They would lack even the necessities and comforts of life. He set them aside.

They forfeited the promise of being a kingdom of priests through unbelief and disobedience.

Vs. 10 In the future (after those days) he will make a new covenant with the house of Israel. He will write the law in their hearts and minds, He will be their God and they will be his people. (This means they are not now his people. They are his at this time only if they accept Christ as the new covenant, just as the Gentiles do. In the future, He will again turn his care and attention to them and they will know Christ and will come under the new covenant as a nation. Maybe not everyone will turn to Jesus, but He will work them as a nation.)
Vs. 11 At that future time nobody will have to teach anybody for they will all know him in their hearts.
Vs. 12 He will be merciful to them for all their unrightousness and he will remember their iniquities no more.
Vs. 13 the first covenant was old, decayed, ready to be done away with, and be replaced with new covenant.
Heb.9:11-15 Christ, the high priest of a greater and more perfect tabernacle that was not built with human hands.
Vs. 12 He became high priest of eternal redemption by entering the Holy place through his own shed blood, not the blood of animals.
Vs. 13 the blood and ashes of animals did sanctify for the purification of flesh. It did not purge anything from them.
Vs. 14 The blood of Jesus does more than that. It purges the conscience from dead works to serve the living God.
Vs. 15  Because of that he is the Mediator of the new testament.

There is no other high priest.
Priesthood conferred on all believers.

No male can make a sacrifice to atone for anyone. There is no mediator between anyone and God except Christ Jesus. No male can mediate for his wife or his children. He can pray for them and he can guide them in the ways of the Lord, but he cannot mediate with God for them. Every individual must come to God with their own sacrifice of repentance, praise of the lips, of their tithes and offerings. Each one must present their bodies to him as a living sacrifice. Individually one worships God in spirit and in truth. Each person stands alone before God. No one can do any of these for someone else. Each individual is their own priest unto God, offering their own service, sacrifices and praises. Just as God promised the people under the old covenant that he would make them priests and a holy nation, he grants the fulfillment of that to those who come under Jesus and the New covenant.

I Pet.2:5,9 "Ye also, as living stones, are built up a spiritual house, an holy priesthood, to offer up spiritual sacrifices, acceptable to God by Jesus Christ." 9. But ye are a chosen generation, a royal priesthood, a holy nation, a people of his own, that ye should show forth the praises of him who called you out of darkness into his marvelous light.

The word "chosen" literally means to be the favored, selected, the choicest. The word "priesthood" here means a sacerdotal function, to perform the functions of a priest, a priestly fraternity. The “office” of priesthood was no longer individuals chosen by God, it became a whole fraternity of every believer who would function in the way of a priest for themselves. The priesthood the Jews forfeited by unbelief and disobedience was then changed. The better covenant under Jesus grants us and them not only the priesthood, but royalty as well

Rev. 1:6 "And He hath made us a Kingdom of priests, unto God and Father, to him be glory and dominion forever and ever. Amen."
Rev.5:10 "And has made us a kingdom of priests and we shall reign on the earth."
Rev. 20:6"—and they shall be priests of God and of Christ and shall reign with him a thousand years." The last two verses are for the future, but the fact remains that even in those verses, there is no distinction made between genders.   Priests are not just males, women believers are included. The promise of priesthood was made to ALL the children of Israel, not just the males.  The promise was fulfilled in ALL believers in Christ, not just in men. Man was not designated by God to be a priest over his household either in the Old Testament or in the New.

Man as priest of his household is a false doctrine that has no biblical basis.

The priesthood is a gift with which one serves God, it was never given as a right of males to be a dominant leaders over households.

The gift of the priesthood of all believers has become a perverse elevation of males to the place of Jesus Christ, making idols of the men and idol worshipers of the women. The doctrine of the priesthood of males over their households is Satan inspired arrogant pride, not Bible truth.