half sister
half-sister
stepsister

So would you want his child for your half sister?

Over the next nine years, Virginia's half sister, father and brother also died.

I'd no idea Dad had any living relatives, let alone a half sister.

Only then did I turn back to my half sister.

And how did they feel about their new half sister?

She could not stop thinking of the woman who was her half sister.

She told me a few days ago that I have a half sister.

Could he have been the father of her half sister?

If her half sister was hiding under another name, why?

John Henry told his half sister about the plan last year.