Ah well...what's the phrase again? Once more, into the breach dear friends.
It is HEAVILY suggested in the game that Laguna is Squall's father, and Raine is his mother. We know from flashbacksRaine born a son while Laguna was out to save Ellone, that Ellone and that son were sent to an orphanage together. Squall calls Ellone 'sis' all the while.
On teh Ragnarok, Laguna says he and Squall have something to talk about, Kiros says it's a good thing Squall doesn't take after his father.
There's without a doubt more 'hints' at Squall being Laguna's son, I advise using the search function. Plenty of threads about this there.
