Service at the altar is the highest honor given to man. For boys, it’s the first stage in becoming a priest. He dresses like a priest in cassock and surplice, and directly helps the priest celebrate the Most Holy Sacrifice of the Mass at the altar in the holy sanctuary. Altar boys are literally the right arms of priests acting in the Person of Christ in the symbolism of Our Lord as Bridegroom.
This symbolism is even reflected in the structure of the Church. The sanctuary is divided from the nave, which represents the division between Heaven, where Christ offers his once-for-all sacrifice to the Father, and the believers on earth, the Church Militant, the Bride preparing for the wedding feast at the end of time. No rites better represent this symbolism than in the East where the sanctuary is sharply divided from the nave by a wall with a narrow opening.
Altar boys, like priests, represent Christ through their extension to priests who carry out the sacrifice.
The reason why females can’t serve at the altar as altar boys falls in line with the reason why they can’t be priests. Males only represent fathers, sons, kings, princes, lords, emperors, and bridegrooms.
You wouldn’t want to see women playing the roles of the Twelve Apostles in a serious movie about Our Lord. Yet, the church of Vatican 2 has already enlisted women to have their feet washed by priests, bishops, and even their pope during Lent, the very symbolism of the Apostles having their feet washed by Christ. It all goes hand-in-hand or is it foot-in-foot?
Women serving the altar destroys the symbolism between Christ and His Church, the Bridegroom and the Bride. It falsifies the mystery of faith, and confuses the natural order between men and women and their roles in Church and society.
Women serving the altar is ultimately a sign of rebellion against the natural law of God.
One solid argument (perhaps the simplest) to prove sedevacantism:
1. The Catholic Church has infallibly taught that its disciplines can’t be harmful or contrary to Divine law, nor can any outward sign used in the celebration of Mass be an incentive to impiety. In fact, the second mark of the Church is holiness, which it wouldn’t be if anything unholy was found in its laws and practices of worship. 
2. The Catholic Church has condemned altar girls as evil and contrary to the Divine law. 
3. Altar girls are outward signs used in the celebration of mass in the church of Vatican 2, which has been approved by John Paul II’s official interpretation of the 1983 Code of Canon Law. 
4. The Vatican 2 church and its pope are not Catholic, thus they aren’t part of the Catholic Church.
Objection # 1: The Bible (Romans 16:1) speaks of a female deaconess (“diakonos” in Greek – sometimes translated as “minister of the Church”) – and they were even allowed to serve at the altar. The Old Catholic Encyclopedia on deaconesses:
“There can again be no question that the deaconesses in the fourth and fifth centuries had a distinct ecclesiastical standing, though there are traces of much variety of custom. According to the newly discovered “Testament of Our Lord” (c. 400), widows had a place in the sanctuary during the celebration of the liturgy, they stood at the anaphora behind the presbyters, they communicated after the deacons, and before the readers and subdeacons, and strange to say they had a charge of, or superintendence over the deaconesses. Further it is certain that a ritual was in use for the ordination of deaconesses by the laying on of hands which was closely modeled on the ritual for the ordination of a deacon.
If widows and deaconesses can serve the altar, then altar girls wouldn’t be contrary to Divine law, nor would it necessarily follow that they are harmful or evil.
Answer: There are two facets to the objection. First, it doesn’t say that deaconesses or widows served at the altar. Secondly, “Testament of Our Lord” demonstrates what was seen at the time. Other apocryphal documents speak of the same practices of women at that time. That doesn’t mean the Church permitted or approved such practices by law. In fact, many things were seen in churches which were condemned by the Church. A few paragraphs later, the Catholic Encyclopedia makes a special point how the Council of Laodicea condemned practices seen in Church and specifically women serving at the altar. The same council also condemned those apocryphal writings that referred to women serving in the sanctuary, etc. However, we also have early documents that explain how deaconesses took Communion to other women, but were not permitted to enter the sanctuary to retrieve it.
Objection # 2: Consider, “And I commend to you Phoebe, our sister, who is in the ministry of the Church, that is in Cechreae: That you receive her in the Lord as becomes saints and that you assist her in whatsoever business she shall have need of you. For she also has assisted many, and myself also.” (Rom. 16:1)
Thus, women served the clergy.
Answer: It doesn’t say they served them at the altar. Sure, women served the Church by baptizing, instructing, and helping other women. That is how history has portrayed it. When history showed deaconesses acting as priests, serving the altar, etc., the Church condemned it.
Objection # 3: The Church has been given the power of binding and loosing. Therefore, the Church has the power to loosen the prohibition of women serving the altar.
Answer: The Church was not given power to loosen Natural or Divine Law. Altar girls are an “evil practice” according to the Church. The Church can’t make an evil practice into something that leads to piety at mass.
Objection # 4: Altar girls are not a serious enough issue. It’s not like they are making women priests which is a serious matter.
Answer: Another writer rightly pointed out, “We could say that a woman or girl serving at the altar, no matter how devout her personal intentions, no matter how reverent, recollected and modest her deportment and dress, is by her very presence in the sanctuary engaging in what is objectively a kind of spiritual immodesty. She is flirting, as it were, with the goal of priestly ordination – mimicking it, drawing as near as she can to it with an indecorous familiarity and an intrusive intimacy. Her liturgical role insinuates and suggests ordination as its proper goal or fulfillment, even though this is absolutely excluded by the Law of Christ.” (Rev. Brian Harrison)
Unfortunately, Harrison misses the point that a woman serving the altar in any capacity is absolutely excluded by the Law of Christ.
Objection # 5: It’s not a universal law or discipline. Therefore, it doesn’t qualify as something the Church can’t do.
Answer: Two points: First, it is a universal law because a liturgical law that involves the whole Latin rite qualifies as a universal law. Secondly, it wouldn’t matter if it were not a universal law because Canon 7, Session 22 of the Council of Trent refers to outward signs used in Mass.
 The Council of Trent, Session XXII, Can. 7.
If anyone says that the ceremonies, vestments, and outward signs, which the Catholic Church uses in the celebration of Masses, are incentives to impiety rather than the services of piety: let him be anathema [cf. n. 943]. (D. 954).
Pope Leo XIII, Satis Cognitum #9 (1896):
For, since Jesus Christ delivered Himself up for the salvation of the human race, and to this end directed all His teaching and commands, so He ordered the Church to strive, by the truth of its doctrine, to sanctify and to save mankind. But faith alone cannot compass so great, excellent, and important an end. There must need be also the fitting and devout worship of God, which is to be found chiefly in the divine Sacrifice and in the dispensation of the Sacraments, as well as salutary laws and discipline. All these must be found in the Church, since it continues the mission of the Saviour for ever. The Church alone offers to the human race that religion – that state of absolute perfection – which He wished, as it were, to be incorporated in it. And it alone supplies those means of salvation which accord with the ordinary counsels of Providence.
Pope Gregory XVI, Mirari Vos, # 9 (1832): “Furthermore, the discipline sanctioned by the Church must never be rejected or branded as contrary to certain principles of the natural law. It must never be called crippled, or imperfect or subject to civil authority. In this discipline the administration of sacred rites, standards of morality, and the reckoning of the Church and her ministers are embraced.”
Pope Gregory XVI, Quo Graviora, # 4-5 (1833): “…[the evil “reformers”] state categorically that there are many things in the discipline of the Church in the present day, in its government, and in the form of its external worship which are not suited to the character of our time. These things, they say, should be changed, as they are harmful for the growth and prosperity of the Catholic religion, before the teaching of faith and morals suffers any harm from it. Therefore, showing a zeal for religion and showing themselves as an example of piety, they force reforms, conceive of changes, and pretend to renew the Church. While these men were shamefully straying in their thoughts, they proposed to fall upon the errors condemned by the Church in proposition 78 of the constitution Auctorem fidei (published by Our predecessor, Pius VI on August 28, 1794). They also attacked the pure doctrine which they say they want to keep safe and sound; either they do not understand the situation or craftily pretend not to understand it. While they contend that the entire exterior form of the Church can be changed indiscriminately, do they not subject to change even those items of discipline which have their basis in divine law and which are linked with the doctrine of faith in a close bond? Does not the law of the believer thus produce the law of the doer? Moreover, do they not try to make the Church human by taking away from the infallible and divine authority, by which divine will it is governed? And does it not produce the same effect to think that the present discipline of the Church rests on failures, obscurities, and other inconveniences of this kind? And to feign that this discipline contains many things which are not useless but which are against the safety of the Catholic religion? Why is it that private individuals appropriate for themselves the right which is proper only for the pope?”
Pope Pius XII, Mystici Corporis, # 66 (1943): “Certainly the loving Mother is spotless in the Sacraments, by which she gives birth to and nourishes her children; in the faith which she has always preserved inviolate; in her sacred laws imposed on all; in the evangelical counsels which she recommends; in those heavenly gifts and extraordinary graces through which, with inexhaustible fecundity, she generates hosts of martyrs, virgins and confessors.”
 Council of Laodica 4th Century
Canon 44: Women may not go to the altar.
This canon is found in all collections of canons in the Church both East and West.
Pope Gelasius 494 AD:
We have heard with sorrow of the great contempt with which the sacred mysteries have been treated. It has reached the point where women have been encouraged to serve at the altar, and to carry out roles that are not suited to their sex, having been assigned exclusively to those of masculine gender. (Vatican journal Notitiæ, Aimé-Georges Martimort, vol. 16, 1980) This journal was used as the explanation for John Paul II’s Inæstimabile donum, which affirmed the prohibition of altar girls. Aware this Divine prohibition, John Paul II later rejected the Divine law and permitted altar girls anyway through the Congregation for Divine Worship and the Discipline of the Sacraments in its March 15, 1994 letter.)
ON THE OBSERVANCE OF ORIENTAL RITES
Encyclical of Pope Benedict XIV promulgated on July 26, 1755 Allatae Sunt:
Women Assisting at Mass
Pope Gelasius in his ninth letter (chap. 26) to the bishops of Lucania condemned the evil practice which had been introduced of women serving the priest at the celebration of Mass. Since this abuse had spread to the Greeks, Innocent IV strictly forbade it in his letter to the bishop of Tusculum: “Women should not dare to serve at the altar; they should be altogether refused this ministry.” We too have forbidden this practice in the same words in Our oft-repeated constitution Etsi Pastoralis, sect. 6, no. 21.
1917 Code of Canon Law. Canon 813, §2:
The minister serving at mass should not be a woman unless, in absence of a man, for just cause, it is so arranged that the woman respond from afar and by no means approach the altar.
1917 Catholic Encyclopedia, Woman
Ministering at the altar, even in a subordinate capacity, is likewise forbidden. A decree says: “It is prohibited to any woman to presume to approach the altar or minister to the priest” (cap. Inhibendum, 1 de cohab.); for if a woman should keep silence in church, much more should she abstain from the ministry of the altar, conclude the canonists.
 The 1983 Code of Canon Law, Canon 230 §2: Lay persons can fulfill the function of lector in liturgical actions by temporary designation. All lay persons can also perform the functions of commentator or cantor, or other functions, according to the norm of law.
On March 15, 1994, the Congregation for Divine Worship and Discipline of the Sacraments to presidents of episcopal conferences announced a June 30, 1992 authentic interpretation (confirmed by John Paul II on July 11, 1992) from the Pontifical Council for the Interpretation of Legislative Texts. This authentic interpretation said that canon 230 §2 permits service at the altar by women, but the local bishop may decide whether to allow them in his diocese.