SAN JOSE — Ileana and Miguel Yamuni desperately wanted to start a family, but just couldn’t conceive. They went to a clinic, and began the lengthy and expensive process of attempting pregnancy with the help of in-vitro fertilization, or IVF. Ileana had begun the hormone therapy to ready her eggs for extraction, after which they would be joined with her husband’s sperm in a lab. Then the Costa Rican government forced them to halt.