Why is ethinyl used instead of methyl in clinical steroids such as those used in birth control?

Question

In most steroids 17a-methylation is what is used to prevent the 17b-hydroxy group from being cleaved. Why is it that in most newer age steroidal products 17a-ethinyl is used instead? Are there any advantages to this as far as bioavailability is concerned?

Answer 1

Ethinyl steroids are more soluble start action quicker.