While owning property in joint tenancy does avoid probate, this estate planning method comes with certain negative tax consequences. Transfers in joint tenancy expose those assets to the joint tenant's debts and creditors, creates a gift tax liability when granted to a non-spouse, disinherit children of first marriage when the joint tenancy is given to a second marriage spouse, and most notably – defeats the step-up tax basis between husband and wife at the first death, because only the deceased spouse's cost basis gets the step up in value, and the surviving spouses does not.