My wife and I are gifting $27,000 to our son and his wife to purchase a house. That's within the limit allowed for a joint gift. Does it matter if it's from a joint acct?

[Coleen3]

No, the account where it came from is irrelevant.

Gift splitting is allowed for parents so that they can each give $14,000 to a child.  You can give  away $14,000 to as  many  individuals as you 'd like. A husband and wife can each make $14,000  gifts. 

[Hal_Al]

You can give them more than $28,000. You give them up to $56,000 without having to file a gift tax return. You give your son $14K, you give your daughter-in-law $14K. Your wife also gives each of them $14K.

"Gift Tax" is somewhat of a misnomer.  Even though a gift tax return may be required, very few people ever actually pay federal gift tax. The purpose of the gift tax return is usually only to document a reduction in the allowable estate tax exemption. So, you can gift them any amount (up to $11.2 million) tax free.
See <a rel="nofollow" target="_blank" href="https://turbotax.intuit.com/tax-tools/tax-tips/Tax-Planning-and-Checklists/The-Gift-Tax-Made-Simple/...>