Merriam-Webster defines “parent,” primarily, as “a person who is a father or mother” or “a person who has a child.” However, because not all parents are heterosexual couples or identify as men and women, this is why “parent” is used for both “mother” and “father” when the gender of a parent is not known.
You may see different use in PPIs, IFSPs and TPEs because each consumer might have both parents or just one. It is recommended to use the term in Spanish accordingly:
ST: parent
Translation:
1. Padres: use plural for general language and when both parents are included.
2. Padre / madre: use singular if you consider this translation is more appropriate when there is only one parent included.
3. Madre: use singular in feminine when you came across with the text that states the father is not involved o there is no any relation with the child.