Although someone with a Sagittarius Sun can have a Gemini Mars, these two positions combined can reduce the number of possible birth years to a very small number among people potentially alive today.In fact, only if born in 1943, 1975 and 1990 (plus a very few in 1928) could someone alive today have a Sagittarius Sun and Gemini Mars. A Leo or Virgo alive today would need to be born in 1956 or 2003 to have Mars in Pisces, and 1971 (no other year) to have Mars in Aquarius. Born in 1924, Leos (e.g. Phyllis Schlafly) and early Virgos had Mars in Pisces and late Virgos Mars in Aquarius, but this does not diminish the rarity of such placings or indeed of these natal Mars signs overall.
Even an Aquarius with Mars in Leo alive today could be born only in 1916 (very old!), 1931, 1948 (a few), 1963 (e.g. Michael Jordan), 1995 or 2010. A Pisces with Mars in Virgo could only be born in 1918, 1933, 1965, 1980, 1997 or be seven months old now. In contrast, even though Mars in Pisces is at perihelion, a Pisces with Mars in Pisces alive today could be born in any of 1917, 1919, 1932, 1934, 1947, 1949, 1951, 1964, 1966, 1979, 1981, 1994, 1996, 1998 or 2011, plus a few in 1930, 1962, 1983 and 2009. A Leo with Mars in Leo could be born in any of 1921, 1923, 1925, 1936, 1938, 1940, 1953, 1955, 1957, 1968, 1970, 1972, 1983, 1985, 1987, 1989, 2000, 2002 and 2004, plus a few in 1919, 1927, 1942, 1951, 1974 and 1998.
With the asteroids, its notable that Ceres has its perihelion on the opposite side to Mars, and a Pisces with Ceres in Virgo alive today must have been born in 1917, 1940, 1963, 1986 or 2009, which is one of every five Ceres orbits. In contrast, a Pisces with Ceres in Pisces could be born in 1919 (a few), 1924, 1933 (a few), 1938, 1942 (a few), 1947, 1956, 1961, 1965 (a few), 1970, 1979, 1984, 1993, 2002 or 2007.
The more eccentric asteroid Juno has perihelion in Taurus/Gemini, and only if born in 1957/1958 or 2005/2006 will people alive today with the Sun between Libra and Aquarius have Juno in Gemini. To have Juno in Taurus with the Sun between Virgo and Capricorn somebody now living would need to be born in 1922 (very old!) or 1970, whilst to have Juno in Cancer with the Sun between Scorpio and Pisces one would have to be born in 1931/1932, 1979/1980 (e.g. my brother) or 1992/1993. Having Juno in Aries with the Sun between Leo and Sagittarius would mean being born in 1935 or 1983. People with the Sun between Leo and Capricorn in 1948/1949 and 1983/1984 may have Juno in Aries (predominant in the first case) or Taurus (in the second). People with the Sun between Libra and Pisces in 1944/1945 will have Juno in Cancer in late 1944 and in Gemini from the start of 1945.