Which is more advantages to file married jointly or separated?

which is more advantages to file married jointly or separated?
Well, unless you are divorced, you must file "Married Filing Jointly...."
The only way I see the benefits changing is if you have another child... but I still think Married Filing Jointly is better, simply because it's what the law says:p

Kepi is wrong; you do NOT have to file jointly.

Normally, filing jointly provides the most benefits, but NOT all the time.

There are so many variable that the only way to see which is best is to do it BOTH ways and compare the results.