  The "second-parameter effect" is characterized by the existence of globular
clusters (GCs) with similar metallicity [Fe/H] (the "first parameter") but
different horizontal-branch (HB) morphologies. One of the primary
second-parameter candidates is cluster age. In the present paper, we address
the following issue: "Are the age differences between second-parameter GCs, as
derived from their main-sequence turnoff properties, consistent with their
relative HB types?" In order to provide an answer to this question, several
analytical formulae for the mass loss rate on the red giant branch are analyzed
and employed. The case of M5 vs. Palomar 4/Eridanus is specifically discussed.
Our results show that, irrespective of the mass loss formula employed, the
relative turnoff ages of GCs are insufficient to explain the second-parameter
phenomenon, unless GCs are younger than 10 Gyr.
