And, would a loop be more efficient then listing them out one by one?
<select name="birthdayYear" >
<option value="0000"<?php echo $birthdayYear == '0000' ? 'selected="selected"' : ''; ?>>Year:</option>
<option value="2011"<?php echo $birthdayYear == '2011' ? 'selected="selected"' : ''; ?>>2011</option>
<option value="2010"<?php echo $birthdayYear == '2010' ? 'selected="selected"' : ''; ?>>2010</option>
<option value="2009"<?php echo $birthdayYear == '2009' ? 'selected="selected"' : ''; ?>>2009</option>
<option value="2008"<?php echo $birthdayYear == '2008' ? 'selected="selected"' : ''; ?>>2008</option>
<option value="2007"<?php echo $birthdayYear == '2007' ? 'selected="selected"' : ''; ?>>2007</option>
<option value="2006"<?php echo $birthdayYear == '2006' ? 'selected="selected"' : ''; ?>>2006</option>
<option value="2005"<?php echo $birthdayYear == '2005' ? 'selected="selected"' : ''; ?>>2005</option>
<option value="2004"<?php echo $birthdayYear == '2004' ? 'selected="selected"' : ''; ?>>2004</option>
<option value="2003"<?php echo $birthdayYear == '2003' ? 'selected="selected"' : ''; ?>>2003</option>
<option value="2002"<?php echo $birthdayYear == '2002' ? 'selected="selected"' : ''; ?>>2002</option>
<option value="2001"<?php echo $birthdayYear == '2001' ? 'selected="selected"' : ''; ?>>2001</option>
<option value="2000"<?php echo $birthdayYear == '2000' ? 'selected="selected"' : ''; ?>>2000</option>
<option value="1999"<?php echo $birthdayYear == '1999' ? 'selected="selected"' : ''; ?>>1999</option>
<option value="1998"<?php echo $birthdayYear == '1998' ? 'selected="selected"' : ''; ?>>1998</option>
<option value="1997"<?php echo $birthdayYear == '1997' ? 'selected="selected"' : ''; ?>>1997</option>
<option value="1996"<?php echo $birthdayYear == '1996' ? 'selected="selected"' : ''; ?>>1996</option>
<option value="1995"<?php echo $birthdayYear == '1995' ? 'selected="selected"' : ''; ?>>1995</option>
<option value="1994"<?php echo $birthdayYear == '1994' ? 'selected="selected"' : ''; ?>>1994</option>
<option value="1993"<?php echo $birthdayYear == '1993' ? 'selected="selected"' : ''; ?>>1993</option>
<option value="1992"<?php echo $birthdayYear == '1992' ? 'selected="selected"' : ''; ?>>1992</option>
<option value="1991"<?php echo $birthdayYear == '1991' ? 'selected="selected"' : ''; ?>>1991</option>
<option value="1990"<?php echo $birthdayYear == '1990' ? 'selected="selected"' : ''; ?>>1990</option>
<option value="1989"<?php echo $birthdayYear == '1989' ? 'selected="selected"' : ''; ?>>1989</option>
<option value="1988"<?php echo $birthdayYear == '1988' ? 'selected="selected"' : ''; ?>>1988</option>
<option value="1987"<?php echo $birthdayYear == '1987' ? 'selected="selected"' : ''; ?>>1987</option>
<option value="1986"<?php echo $birthdayYear == '1986' ? 'selected="selected"' : ''; ?>>1986</option>
<option value="1985"<?php echo $birthdayYear == '1985' ? 'selected="selected"' : ''; ?>>1985</option>
<option value="1984"<?php echo $birthdayYear == '1984' ? 'selected="selected"' : ''; ?>>1984</option>
<option value="1983"<?php echo $birthdayYear == '1983' ? 'selected="selected"' : ''; ?>>1983</option>
<option value="1982"<?php echo $birthdayYear == '1982' ? 'selected="selected"' : ''; ?>>1982</option>
<option value="1981"<?php echo $birthdayYear == '1981' ? 'selected="selected"' : ''; ?>>1981</option>
<option value="1980"<?php echo $birthdayYear == '1980' ? 'selected="selected"' : ''; ?>>1980</option>
<option value="1979"<?php echo $birthdayYear == '1979' ? 'selected="selected"' : ''; ?>>1979</option>
<option value="1978"<?php echo $birthdayYear == '1978' ? 'selected="selected"' : ''; ?>>1978</option>
<option value="1977"<?php echo $birthdayYear == '1977' ? 'selected="selected"' : ''; ?>>1977</option>
<option value="1976"<?php echo $birthdayYear == '1976' ? 'selected="selected"' : ''; ?>>1976</option>
<option value="1975"<?php echo $birthdayYear == '1975' ? 'selected="selected"' : ''; ?>>1975</option>
<option value="1974"<?php echo $birthdayYear == '1974' ? 'selected="selected"' : ''; ?>>1974</option>
<option value="1973"<?php echo $birthdayYear == '1973' ? 'selected="selected"' : ''; ?>>1973</option>
<option value="1972"<?php echo $birthdayYear == '1972' ? 'selected="selected"' : ''; ?>>1972</option>
<option value="1971"<?php echo $birthdayYear == '1971' ? 'selected="selected"' : ''; ?>>1971</option>
<option value="1970"<?php echo $birthdayYear == '1970' ? 'selected="selected"' : ''; ?>>1970</option>
<option value="1969"<?php echo $birthdayYear == '1969' ? 'selected="selected"' : ''; ?>>1969</option>
<option value="1968"<?php echo $birthdayYear == '1968' ? 'selected="selected"' : ''; ?>>1968</option>
<option value="1967"<?php echo $birthdayYear == '1967' ? 'selected="selected"' : ''; ?>>1967</option>
<option value="1966"<?php echo $birthdayYear == '1966' ? 'selected="selected"' : ''; ?>>1966</option>
<option value="1965"<?php echo $birthdayYear == '1965' ? 'selected="selected"' : ''; ?>>1965</option>
<option value="1964"<?php echo $birthdayYear == '1964' ? 'selected="selected"' : ''; ?>>1964</option>
<option value="1963"<?php echo $birthdayYear == '1963' ? 'selected="selected"' : ''; ?>>1963</option>
<option value="1962"<?php echo $birthdayYear == '1962' ? 'selected="selected"' : ''; ?>>1962</option>
<option value="1961"<?php echo $birthdayYear == '1961' ? 'selected="selected"' : ''; ?>>1961</option>
<option value="1960"<?php echo $birthdayYear == '1960' ? 'selected="selected"' : ''; ?>>1960</option>
<option value="1959"<?php echo $birthdayYear == '1959' ? 'selected="selected"' : ''; ?>>1959</option>
<option value="1958"<?php echo $birthdayYear == '1958' ? 'selected="selected"' : ''; ?>>1958</option>
<option value="1957"<?php echo $birthdayYear == '1957' ? 'selected="selected"' : ''; ?>>1957</option>
<option value="1956"<?php echo $birthdayYear == '1956' ? 'selected="selected"' : ''; ?>>1956</option>
<option value="1955"<?php echo $birthdayYear == '1955' ? 'selected="selected"' : ''; ?>>1955</option>
<option value="1954"<?php echo $birthdayYear == '1954' ? 'selected="selected"' : ''; ?>>1954</option>
<option value="1953"<?php echo $birthdayYear == '1953' ? 'selected="selected"' : ''; ?>>1953</option>
<option value="1952"<?php echo $birthdayYear == '1952' ? 'selected="selected"' : ''; ?>>1952</option>
<option value="1951"<?php echo $birthdayYear == '1951' ? 'selected="selected"' : ''; ?>>1951</option>
<option value="1950"<?php echo $birthdayYear == '1950' ? 'selected="selected"' : ''; ?>>1950</option>
<option value="1949"<?php echo $birthdayYear == '1949' ? 'selected="selected"' : ''; ?>>1949</option>
<option value="1948"<?php echo $birthdayYear == '1948' ? 'selected="selected"' : ''; ?>>1948</option>
<option value="1947"<?php echo $birthdayYear == '1947' ? 'selected="selected"' : ''; ?>>1947</option>
<option value="1946"<?php echo $birthdayYear == '1946' ? 'selected="selected"' : ''; ?>>1946</option>
<option value="1945"<?php echo $birthdayYear == '1945' ? 'selected="selected"' : ''; ?>>1945</option>
<option value="1944"<?php echo $birthdayYear == '1944' ? 'selected="selected"' : ''; ?>>1944</option>
<option value="1943"<?php echo $birthdayYear == '1943' ? 'selected="selected"' : ''; ?>>1943</option>
<option value="1942"<?php echo $birthdayYear == '1942' ? 'selected="selected"' : ''; ?>>1942</option>
<option value="1941"<?php echo $birthdayYear == '1941' ? 'selected="selected"' : ''; ?>>1941</option>
<option value="1940"<?php echo $birthdayYear == '1940' ? 'selected="selected"' : ''; ?>>1940</option>
<option value="1939"<?php echo $birthdayYear == '1939' ? 'selected="selected"' : ''; ?>>1939</option>
<option value="1938"<?php echo $birthdayYear == '1938' ? 'selected="selected"' : ''; ?>>1938</option>
<option value="1937"<?php echo $birthdayYear == '1937' ? 'selected="selected"' : ''; ?>>1937</option>
<option value="1936"<?php echo $birthdayYear == '1936' ? 'selected="selected"' : ''; ?>>1936</option>
<option value="1935"<?php echo $birthdayYear == '1935' ? 'selected="selected"' : ''; ?>>1935</option>
<option value="1934"<?php echo $birthdayYear == '1934' ? 'selected="selected"' : ''; ?>>1934</option>
<option value="1933"<?php echo $birthdayYear == '1933' ? 'selected="selected"' : ''; ?>>1933</option>
<option value="1932"<?php echo $birthdayYear == '1932' ? 'selected="selected"' : ''; ?>>1932</option>
<option value="1931"<?php echo $birthdayYear == '1931' ? 'selected="selected"' : ''; ?>>1931</option>
<option value="1930"<?php echo $birthdayYear == '1930' ? 'selected="selected"' : ''; ?>>1930</option>
<option value="1929"<?php echo $birthdayYear == '1929' ? 'selected="selected"' : ''; ?>>1929</option>
<option value="1928"<?php echo $birthdayYear == '1928' ? 'selected="selected"' : ''; ?>>1928</option>
<option value="1927"<?php echo $birthdayYear == '1927' ? 'selected="selected"' : ''; ?>>1927</option>
<option value="1926"<?php echo $birthdayYear == '1926' ? 'selected="selected"' : ''; ?>>1926</option>
<option value="1925"<?php echo $birthdayYear == '1925' ? 'selected="selected"' : ''; ?>>1925</option>
<option value="1924"<?php echo $birthdayYear == '1924' ? 'selected="selected"' : ''; ?>>1924</option>
<option value="1923"<?php echo $birthdayYear == '1923' ? 'selected="selected"' : ''; ?>>1923</option>
<option value="1922"<?php echo $birthdayYear == '1922' ? 'selected="selected"' : ''; ?>>1922</option>
<option value="1921"<?php echo $birthdayYear == '1921' ? 'selected="selected"' : ''; ?>>1921</option>
<option value="1920"<?php echo $birthdayYear == '1920' ? 'selected="selected"' : ''; ?>>1920</option>
<option value="1919"<?php echo $birthdayYear == '1919' ? 'selected="selected"' : ''; ?>>1919</option>
<option value="1918"<?php echo $birthdayYear == '1918' ? 'selected="selected"' : ''; ?>>1918</option>
<option value="1917"<?php echo $birthdayYear == '1917' ? 'selected="selected"' : ''; ?>>1917</option>
<option value="1916"<?php echo $birthdayYear == '1916' ? 'selected="selected"' : ''; ?>>1916</option>
<option value="1915"<?php echo $birthdayYear == '1915' ? 'selected="selected"' : ''; ?>>1915</option>
<option value="1914"<?php echo $birthdayYear == '1914' ? 'selected="selected"' : ''; ?>>1914</option>
<option value="1913"<?php echo $birthdayYear == '1913' ? 'selected="selected"' : ''; ?>>1913</option>
<option value="1912"<?php echo $birthdayYear == '1912' ? 'selected="selected"' : ''; ?>>1912</option>
<option value="1911"<?php echo $birthdayYear == '1911' ? 'selected="selected"' : ''; ?>>1911</option>
<option value="1910"<?php echo $birthdayYear == '1910' ? 'selected="selected"' : ''; ?>>1910</option>
<option value="1909"<?php echo $birthdayYear == '1909' ? 'selected="selected"' : ''; ?>>1909</option>
<option value="1908"<?php echo $birthdayYear == '1908' ? 'selected="selected"' : ''; ?>>1908</option>
<option value="1907"<?php echo $birthdayYear == '1907' ? 'selected="selected"' : ''; ?>>1907</option>
<option value="1906"<?php echo $birthdayYear == '1906' ? 'selected="selected"' : ''; ?>>1906</option>
<option value="1905"<?php echo $birthdayYear == '1905' ? 'selected="selected"' : ''; ?>>1905</option>
<option value="1904"<?php echo $birthdayYear == '1904' ? 'selected="selected"' : ''; ?>>1904</option>
<option value="1903"<?php echo $birthdayYear == '1903' ? 'selected="selected"' : ''; ?>>1903</option>
<option value="1902"<?php echo $birthdayYear == '1902' ? 'selected="selected"' : ''; ?>>1902</option>
<option value="1901"<?php echo $birthdayYear == '1901' ? 'selected="selected"' : ''; ?>>1901</option>
<option value="1900"<?php echo $birthdayYear == '1900' ? 'selected="selected"' : ''; ?>>1900</option>
</select>
This has the added bonus that you don't have to update it every year.
I don't think you have to worry about efficiency. Using a loop just looks cleaner it will be easier to maintain I think.
1900 is at least as arbitrary as 2011. We can make one that only spans 100 years from the current year.
To get back to 1900 exactly, just change the for condition to 112.