Collocations for parent - noun

married, unmarried
divorced
lone (BrE), single
single-parent families

absent
aged, aging, elderly
deceased, surviving
prospective, would-be
expectant
first-time, new
biological, birth, natural, real
adopted, adoptive, foster
the identities of the adoptive parents

surrogate
custodial, non-custodial (law)
female, male
gay, heterosexual, lesbian
low-income, poor
rich, wealthy, well-to-do
middle-class, working-class
immigrant
working
The government has promised a better deal for working parents.

stay-at-home
good
involved, supportive
The study showed that children with involved parents do better at school.

proud
They have just become the proud parents of a baby girl.

caring, devoted, loving
doting, fond, indulgent
overprotective
stern, strict
bad, unfit
abusive
neglectful
angry, anxious, concerned, distraught, distressed, grieving

company (business)
The subsidiary eventually outgrew its parent company and took it over.