We describe work on the development of immersed boundary methods for sperm motility in
complex fluids. This includes an Oldroyd-B formulation and a Lagrangian mesh method. We
also describe the development of an immersed boundary rheometer for the studying the
properties of viscoelastic fluids. We present preliminary simulation results for the Oldroyd-B
and Lagrangian mesh rheometers and compare sperm motility in Newtonian, Oldroyd-B and
Lagrangian mesh fluids using an existing immersed boundary model for sperm motility.