- An "adoptive parent" is - from the point of view of an adopted child - a parent who has adopted them.
- A "biological parent" is a parent who owns the same blood as their child.
- A "parent-in-law" is the name given to the father or mother of the person's spouse's parents.
[quote] Simplified version: W and X made Y.
Y married Z.
Since W and X are Y's biological parents...
From Z's point of view, W and X are their parents-in-law. [/quote]
A male (or an intersex equivalent) parent-in-law is a "father-in-law".
A female (or an intersex equivalent) parent-in-law is a "mother-in-law". [quote] Simplified version: A and B were married.
A and B made C.
Unfortunately, A and B divorced.
B remarried someone else, B remarried D.
From C's point of view: D is their stepparent.[/quote]
A male (or an intersex equivalent) stepparent is a "stepfather".
A female (or an intersex equivalent) stepparent is a "stepmother". 
