"Planning" a family does not appear to be an exception to the 2 year rule. Actually getting pregnant does. Reference: http://www.journalofaccountancy.com/Issues/2009/Nov/20091783.htm
How much capital gain are you expecting? For people under a certain income level (roughly $106K for Married jointly), a portion of the capital gain is not taxed (technically taxed at 0%).
Example*: couple has $80K income and expects $40K capital gain on home sale of less than 2 years. $26K (106K - 80K = 26K) of the gain will be tax at 0% and $14K taxed at 15%.
*Example assumes couple uses standard deduction. Tax will be less for itemizers.
