https://familysearch.org/search
has some. One - just one, out of thousands - of their collections is "California, Birth Index, 1905-1995". Another is "Texas, Birth Certificates, 1903-1935".
http://usgenweb.org/
has some. Click on the state you are interested in, then look for the county you are interested in and click on it.
http://genealogy.az.gov/
has some - Arizona, over 75 years ago
http://www.wvculture.org/vrr/va_bcsearch.aspx
has some. Here are the first 6 counties and the dates they have for them:
Barbour: 1833, 1853 - 1913
Berkeley: 1860, 1862 - 1913
Boone: 1822, 1832, 1862, 1865 - 1910
Braxton: 1853 - 1862, 1865 - 1913
Brooke: 1852 - 1862, 1864 - 1913
Cabell: 1811, 1853 - 1854, 1856, 1864 - 1865, 1867 - 1913
By now I hope you see something - there ARE free birth records on-line, but there is no comprehensive site. If you specify a time frame and a state (county would be even better) we may be able to direct you to a site that will meet your needs.
However, I suspect you are looking for someone born in the last 20 years; with very rare exception those records are not on-line, to prevent identity theft.
I also suspect you won't bother to add details or ask a a new question with a state and date range. You probably won't be able to read this far on your smart phone, either. I tried, though.