Flexing his parliamentary muscle and flashing his antipathy to efforts to regulate the use of bathrooms by transgender people, House Speaker Joe Straus prevented amendments on the matter from reaching the House floor on Tuesday.

In a showdown with his most socially conservative members, Speaker Joe Straus ended debate on a bill about the fate of the Texas Railroad Commission, which regulates oil and gas operations, by announcing there were no further amendments to consider.

But at least two amendments had been filed before the debate seeking to fold the contentious transgender bathroom issue into the relatively tame oil and gas bill.

State Rep. Matt Schaefer, R-Tyler, second from left, talks to state Rep. Jeff Leach, R-Plano, from left, state Rep. Bill Zedler, R-Arlington, state Rep. Dustin Burrows, R-Lubbock, and state Rep. Cole Hefner, R-Mt. Pleasant in the House Chamber at the Capitol on Tuesday March 28, 2017. JAY JANNER / AMERICAN-STATESMAN

Jay Janner/Austin American-Statesman

The lawmakers were voting to continue the Texas Railroad Commission, which would be abolished Sept. 1, unless continued by the Legislature.

Straus said he had determined the proposed amendments "were not germane" to the bill.

A proposal by Matt Schaefer, R-Tyler, required that bathrooms in buildings owned or leased by the commission shall "be designated for and used only by persons of the same biological sex."

Another proposal, by state Rep. Tony Tinderholt, R-Arlington mandated that when determining whether a company qualifies as a "historically underutilized business," often based on ownership one or more women, "the term ‘woman’ or ‘women’ shall mean the physical condition of being female, as stated on a person’s birth certificate."