The etymology of the term only-begotten leads us to the Late Latin word unigenĭtus. The first meaning cited in the Dictionary of the Royal Spanish Academy (RAE) refers to an only child.
The only one generated, in this table, is the descendant of a couple that has no other descendants. Therefore the only begotten has no siblings. When two people have their first child, it becomes the only one begotten. This condition is left behind if his parents later have one or more children: in this case, the only-born becomes the first-born (that is, the first-born in terms of birth order).
Suppose that Carlos and Mariana have a son, named Pedro. Years go by and the family does not grow. Pedro, therefore, is the only son of Carlos and Mariana. Now let’s take the married couple formed by Javier and Laura. The family group grows with the arrival of Marcos and continues to expand with the births of Silvia, Jorge, Nilda and Bautista. It turns out that Marcos only spawns for a short time, although he always maintains his status as the firstborn. In the field of religion, there is a quintessential use of this notion. The Son of God is called the Only Begotten: in this context, Only Begotten is capitalized. This meaning of the concept appears in the Bible and is a translation of the Greek monogenes, which refers to one who is unique in his kind. It is important to clarify the definition of the Holy Trinity, which establishes that God is Father, Son and Holy Spirit.