In multichild families, youngest children are viewed as the most fragile and needing parental protection. After all, the youngest child in the family is viewed as the baby, the jewel, and the precious one. H/she is the one who is adored, even adulated by parents and other family members. Since h/she is the baby of the family, it is considered that h/she will be in MOST NEED physically, emotionally, and even psychically.
The youngest child furthermore by virtue of his/her ordinal birth order is also the one who will receive the most preferential treatment over his/her oldest/older siblings. H/she will get away w/things that his/her oldest/older siblings would be chastised, even punished for. H/she also has the LEAST responsibilities of any birth order. H/she is seen as "too young" to do certain things and assume responsibilities because h/she is THE BABY. H/she uses this fact to get away with things, get away from doing things, and using the fact of being the youngest to coax and get the most attention possible. After all, NO ONE can/should deny THE BABY the attention h/she needs.
The youngest child is considered by parents and sometimes by oldest/older siblings as incapable of taking care of himself/herself. H/she is viewed as vulnerable by parents. Even as adults, this label sticks with the youongest child who oftentimes must out-prove and outdo others in the family to prove that h/she is capable and responsible. Many times, h/she falls into the label of being "the baby who cannot take care of himself/herself" because of the expectations of parents and siblings who maintain that H/SHE CAN'T. So the H/SHE CAN'T becomes a self-fulfilling prophecy for the youngest child.
Also the youngest child is NEVER disposable as the oldest/older children in the family were. This factor furthermore is correlated to him/her receiving the lion's share of parental attention. Then the remaining factor is that the youngest child is THE LAST child in the family. Parents do not intend to let go of the youngest child SO FAST so they will give him/her the attention-pamper, indulge, even spoil and infantilize him/her for if/when he/she grows up, their parenting role is.....OVER.