Methods for reversible male birth control

A method, comprising:

• providing a polymer;
• adding a thinning agent to the polymer to create a polymer solution of the polymer with a temporarily reduced viscosity prior to injecting the polymer solution into a subject, wherein the polymer solution includes a ratio of the polymer to the thinning agent in a range of 10:1 to 1:1;
• performing a single injection into a vas deferens of the subject, wherein:
• the single injection comprises injecting the polymer solution into the vas deferens of a subject while the viscosity of the polymer is temporarily reduced, and
• the thinning agent of the polymer solution is configured to be metabolized by the subject with the polymer of the polymer solution remaining in the vas deferens to create a polymer barrier to sperm in the vas deferens after elapse of a first amount of time subsequent to the single injection into the vas deferens to render the subject temporarily infertile;
• at a desired time after elapse of a second amount of time subsequent to the polymer barrier being created in the vas deferens defining a contraception period of time, locating the polymer barrier in the vas deferens;
• and
• subsequent to locating the polymer barrier in the vas deferens, injecting a calcium chelator directly into the polymer barrier created in the vas deferens to degrade the polymer barrier and reverse the temporary infertility of the subject at the desired time,
• wherein:
• the calcium chelator is not injected into in the vas deferens prior to the desired time when reversal of the temporary infertility is desired, and
• the calcium chelator does not reside in the vas deferens during the contraception period of time.

A method, comprising:

• providing a polymer;
• adding a thinning agent to the polymer to create a polymer solution of the polymer with a temporarily reduced viscosity prior to injecting the polymer solution into a subject, wherein the polymer solution includes a ratio of the polymer to the thinning agent in a range of 10:1 to 1:1;
• and
• performing only a first single injection into a vas deferens of the subject at a first time at which contraception is desired, the first single injection comprising injecting the polymer solution into the vas deferens of the subject while the viscosity of the polymer is temporarily reduced to create only a polymer barrier in the vas deferens of the subject,
• wherein:
• the thinning agent of the polymer solution is configured to be metabolized by the subject,
• the polymer of the polymer solution remains in the vas deferens of the subject to form a polymer barrier for sperm in the vas deferens after elapse of a first amount of time to render the subject temporarily infertile for a contraception period of time subsequent to performing the first single injection, and
• the polymer barrier resides alone in the vas deferens during the contraception period of time.