The samskaras begin with garbhadhana, that is from the moment of conception [or, more correctly, impregnation]. The "sarira-pinda" must be formed to the chanting of mantras. People mistakenly think that rites like Pumsavana and simanta are meant for the mother. Actually, they are for the life taking shape in her womb, the foetus and are meant to purify it. The elders have a responsibility in this matter. One may not do the rites meant for oneself, but it is sinful to be negligent about those meant for another life. Nowadays people omit to perform garbhadhana, simanta, etc, since they think that such rites are not fashionable.
Where there should be some delicacy in man-woman relationship people act without any sense of shame after the fashion in the West. But, when it comes to performing Vedic rites in which the well-being of the new life created is involved, they feel a sense of awkwardness. Such an attitude is not right.
Garbhadhana, pumsavana and simanta are performed before the child is born. The sexual union of man and wife must be sanctified by the mantras. Instead of being an act of animal passion, it is raised to the level of a samskara with the chanting of mantras: the purpose is the well-being of the life to be formed. It is madness to give up such rituals without realising the high principles inspiring them and, instead, thinking them to be "uncivilized". If there is any feeling of delicacy on your part about the garbhadhana (rtusanti) ceremony, you do not have to invite a crowd. But the rite itself must be gone through within the four walls of the home. It is no longer the custom to have a four-day wedding with the couple doing daily aupasana. Nor is the rite of sesahoma conducted following the day of wedding. The couple have sexual intercourse on the same day as the marriage without any ceremony and the chanting of mantras. This is an evil practice and sinful. Since the intercourse takes place in an animal manner, the children born too will be likewise. Pumsavana must be performed in the third month of pregnancy and simanta in the sixth or eighth. Nowadays both rites are gone through together anyhow.
On the birth of a child, its jatakarma must be performed. Gifts must be given away. Namakarana is on the eleventh day. Even this, the naming ceremony, has a purificatory purpose according to the sastras. There are rules regarding the name to be chosen for the child in accordance with the naksatra or asterism under which it is born. It must be one from the many names of the Lord and to call the child by such a name is itself a samskara since it has a cleansing effect. We do not have the custom of "christening" our children as "Longfellow" or "Stone". But nowadays even in this land similar names are given to children. Also when the child's name is that of the Lord it is corrupted or twisted clumsily. The name given to a child during a Vedic ritual must be treated with some respect.
When the child is six months old it is time for its annaprasana. The samskaras from the garbhadhana to namakarana are performed by the parents on behalf of the child. In annaprasana, even though the father chants the mantras, it is [obviously] the child that takes anna or food.
If the mother takes medicine, the baby is nourished, is it not? In the same way the inner thoughts and feelings of the parents will affect the foetus and its character will be shaped accordingly. There is a difference between what you write when your mind is calm and what you write when you are in an angry mood: the first will be good to read while the second will not be so pleasant. The body too is subject to good and bad influences. The sexual union must take place when the couple are imbued with good thoughts: it will then lead to the creation of a blob of life (pinda) that will have the potential to develop into a noble character. This is the reason why the marriage is consummated with the intonation of mantras.
There are people who have not altogether ceased to observe such rites, but sometimes they go through two or three rites together. There is a right time for every samskara and there are mantras as well as dravyas (materials) appropriate to them.
Caula comes after annaprasana. It is meant for the "sikha" which is essential to the conduct of all good rites. The sannyasin has no sikha and is shaven-headed; in fact, the sikha has to be removed with the recitation of mantras at the time one receives initiation into sannyasa. It is worn in the caula ceremony with the chanting of mantras and with a vow made to Paramesvara (as part of the samkalpa). So it is wrong to remove it as we like in violation of this vow. Is it proper to remove this lock of hair as if it were just a handful of leafy vegetables? People install the sivalinga or salagrama for worship. Would it be right on their part to discard them as they like. It would be a different matter if they were stolen or lost accidentally. Similarly, to wear a sikha ceremonially and then remove it, as and when we like, and wear a crop is not proper.
The chanting of the Vedas, the performance of Vedic rituals and the dharma practised by the householder with his wife strengthen both body and mind (the latter through the vibrations in the nadis produced by the mantras). The sikha on the Brahmarandhra is a protection and a means of obtaining such strength. It is like the tiles on the roof of a house. Only when you cease to perform Vedic rites is it not needed, that is when you are no longer a householder and became an ascetic. Today even as student-bachelors or as householders we have ceased to chant the Vedas and practise Vedic rites. So, naturally, we do not wear the sikha also.
Upanayana comes after caula. It is the first samskara that a boy performs, chanting the mantras himself. Those conduced until this ceremony are meant to protect the child from the evil influences arising from the sins committed by its parents. These are either "garbhika" or "baijika" (belonging to the womb or to the seed or sperm). The samskaras performed by the parents are to remove the ills caused to the child by these harmful influences.
Any samskara must be performed at the right time and by doing so we are absolved of our sins. To wash away the papa earned by us in the past we have to go through samskaras in which our body, mind and speech are applied.
We think evil with our mind, tell lies with our mouth, and sin with our body also. Indeed we practise all kinds of deception. The wrongs committed by mind, speech and body must be wiped away by applying mind, speech and body to virtuous purposes. With the mind, Paramesvara must be meditated upon; with the faculty of speech, mantras must be chanted; and with the body, noble deeds must be performed. It is from the time of upanayana that one becomes mature enough to perform samskaras that bring together mind, speech and body.
I must speak about another matter. Apart from the samskaras that a father performs specifically for the sake of his child (from garbhadhana to caula), those (including other types of rites) he conducts otherwise also benefit the children. This is according to the saying, "The good done by mother and father goes to protect the children". Until recently the children of Vaidika Brahmins were particularly bright, the reason being the impetus they received from the samskaras performed by their forefathers. What our ancestors did by way of good works served as the foundation of our moral and intellectual uplift for two or three generations. Children born afterwards have been so much embroiled in worldly affairs as to have become degraded.
Our fathers did not perform any samskaras. So we may feel sorry that we have been deprived of the benefits that would otherwise have come to us. Let us not give room for our children to make the same complaint about us. Let us perform samskaras for our sake and theirs.
For a general background, please see here