Vital statistics in New York prior to 1880 were originated & filed in the town/city clerk's offices. They are rarely if ever online. Town & Village of Whitehall, http://s543754877.initial-website.com/village/
You're lucky you know which town/city they were living in. Most people don't know that info.
Also I'd look at the Research Library of the Historical Society of Whitehall, www.skenesborough.com/historical-society/
. They have a wide list of items at their library. Successful Searching!