While all Jews are special and beloved in the eyes of HaShem, there are certain "privileged characters" who command an extra dose of honor. These include a king, a kohen, a chatan and kallah, and.the b'chor - the first-born.
Originally, the first-born were to be the spiritual leaders.


Originally, the first-born were to be the spiritual leaders.

Originally, the first-born were to be the spiritual leaders who would administer the Mishkan. But when they sinned with the Golden Calf, that holy task was taken away from them and given instead to the lineage of Aharon.
Yet, still, there are special considerations given to the b'chor. Every erev Pesach (this year, Thursday), the first-born either fast or participate in a siyum, in order to acknowledge having been saved in the final plague of makat b'chorot. And first-born sons must be redeemed in the Pidyon HaBen ceremony a month after they're born.
An interesting question arises. According to Halacha, a boy is redeemed only if he is the natural first-born to his mother. But if the child is the first for the father but not for the mother, or is born by c-section, or follows a miscarriage, then he is not considered a b'chor.
In Egypt, however, we are told that all the first-borns - both for the mother and the father were slain. So why don't we follow that same rule in the pidyon haben ceremony? Especially since that's the source of the whole mitzvah.
Rabbi Frand quotes an answer by the Avnei Shoham: The essential message of the Exodus is hakarat hatov, appreciation for HaShem intervening in history and saving us, as well as His ongoing generosity and benevolence for us. A human being has a tendency to take things for granted, to only turn to G-d when things go wrong, but not when things go right. Pesach helps us to correct this.
Every birth is a miracle.


Every birth is a miracle.

The mitzvah of b'chor has a similar message. When couples have trouble having children, they turn to G-d for help. But when things go normally and naturally, they tend to be complacent and forget that every birth is a miracle. The pidyon haben reminds us that just as HaShem protected the first-born in Egypt, so He protects every child in every generation.
The Torah, however, chose to give us this reminder only when everything goes normally, as "expected." For that is when people might forget G-d's role. When things don't go as planned - when the baby must be delivered through surgery, when the mother had a previous miscarriage or a former marriage that didn't work out - the couple is already painfully aware of how fragile and tenuous life can be, and they don't need the mitzvah of b'chor to remind them.
May we have b'rachah every day of the year - and thank G-d for it.