If the Twilight Saga proved anything, it's that teen girls will pay good money to be driven to tears. So this summer we have two entries into the teen-weepie genre.

If I StayChloe Moretz in 'If I Stay'

The Fault in Our Stars has already set box office receipts spinning, raking in nearly $300 million worldwide since its release in June. It's also had a strong reception from audiences (82% positive on IMDb) and critics (80% positive on Rotten Tomatoes).

More: read our review of 'If I Stay'

It's hardly surprising that the summer's second adolescent tearjerker If I Stay has had a harder time with critics, who admittedly aren't in the key demographic and are unlikely to be nice to two movies aimed at pre-pubescent girls. But audiences have enjoyed it (71% positive on IMDb) since its release last week in America, and it expands globally from this week onward. On the other hand, it has a long way to catch up financially: If I Stay earned $16 million at the US box office in its opening weekend, compared with $48 million for The Fault in Our Stars.

More: 'If I Stay' may be average - but it's the best of a bad box-office bunch

The teen-weepie trend is as old as the movies themselves, reaching its climax in 1970 with the fatal-illness romance Love Story, starring Ryan O'Neal and Ali McGraw. Since then, key examples have included My Girl (1989), Titanic (1997) and several young-romance films based on Nicholas Sparks books, including A Walk to Remember (2002), The Notebook (2004), Dear John (2010) and The Last Song (also 2010). Clearly this isn't a trend that will end soon.

Watch the trailer for 'If I Stay':