Son of the Demon was written *in* continuity in the late 80's. Some decision was made in the mid-90's (I guess...I quit well before then) to say it wasn't, though the story had no bearing on normal Batman comics.
In Son of the Demon:
Warning Spoiler! Click to showBruce and Talia are married with Ra's consent (they have teamed up to track down a much worse killer). She gets pregnant and he gets somewhat protective. In the penultimate conflict, she gets hurt. Bruce is told that Talia miscarried (somewhat devastating to an orphan). Batman finishes the job, and leaves them. Several months later, Talia gives birth. It ends with a lucky couple in the middle of nowhere being given a perfectly healthy baby (boy, I believe). The End. The idea is that Batman and Talia have a baby, being raised by a regular family somewhere.
Furthermore, Kingdom Come takes it a little further:
Warning Spoiler! Click to showAnd their son is currently the head of the Al Ghul empire, and is the spitting image of his father. It's just background to the real story of Kingdom Come. I simply included it to show that THEY (Mark Waid and Alex Ross) took it as in continuity DC history.
That's all irrelevant. Talia is a very Bond-like character...beautiful, deadly, in love with the hero, but the daughter of a great villain.