Join/indexes question

[SOL MYR]

Hi,

Say I need to SELECT "people that are either Musicians themselves, or have a Musician kid".
Note I show only grownups (not kids, even if they triggered the selection of their parents).

My tables are PERSON and KID, each has a HOBBY column (with might be "music"), plus INDEX on it.
PERSON table:
- ID (primary key)
- HOBBY (with INDEX on it)
KID table:
- ID
- HOBBY (with INDEX on it)
- PARENT_ID (foreign key)

What's the best way to query, assuming I have millions of people, but musicians are rare?

1) I tried a naiive nested select, but it seems inefficient:
SELECT * from PERSON
WHERE PERSON.HOBBY='music' or EXISTS(select* from KID where PARENT_ID=PERSON.ID and HOBBY='music')

2) I tried to unite 2 different selects, and it's efficient but not very readable:
SELECT* from PERSON where HOBBY='music'
UNION
select PERSON.* from PERSON inner join KID on KID.PARENT_ID=PERSON.ID
where KID.HOBBY='music'

Is there a way to achieve efficiency, while still keeping it readable?
Thanks.