According to its website, Visions in Methodology "is designed to address the broad goal of supporting women who study political methodology" and "serves to connect women in a field where they are under-represented." The Call for Proposals for the 2017 VIM conference indicates that submissions were restricted to women:
We invite submissions from female graduate students and faculty that address questions of measurement, causal inference, the application of advanced statistical methods to substantive research questions, as well as the use of experimental approaches (including incentivized experiments)...Please consider applying, or send this along to women you believe may benefit from participating in VIM!
Here is the program for the 2016 VIM conference, which lists activities restricted to women, lists conference participants (which appear to be only women), and has a photo that appears to be from the conference (which appears to have only women in the photo).
The 2017 VIM conference webpage indicates that the conference is sponsored by several sources such as the National Science Foundation and the Stony Brook University Graduate School. But page 118 of the NSF's Proposal & Award Policies & Procedures Guide (PAPPG) of January 2017 states:
Subject to certain exceptions regarding admission policies at certain religious and military organizations, Title IX of the Education Amendments of 1972 (20 USC §§ 1681-1686) prohibits the exclusion of persons on the basis of sex from any education program or activity receiving Federal financial assistance. All NSF grantees must comply with Title IX.
The VIM conference appears to be an education program or activity receiving Federal financial assistance and, as such, submissions and conference participation should not be restricted by sex.
1. This Title IX Legal Manual discusses what constitutes an education program or activity:
While Title IXs antidiscrimination protections, unlike Title VIs, are limited in coverage to "education" programs or activities, the determination as to what constitutes an "education program" must be made as broadly as possible in order to effectuate the purposes of both Title IX and the CRRA. Both of these statutes were designed to eradicate sex-based discrimination in education programs operated by recipients of federal financial assistance, and all determinations as to the scope of coverage under these statutes must be made in a manner consistent with this important congressional mandate.
2. I think that the relevant NSF award is SES 1324159, which states that part of the project will "continue a series of small meetings for women methodologists that deliberately mix senior leaders in the subfield with young, emerging scholars who can benefit substantially from such close personal interaction." This page indicates that the 2014 VIM conference received support from NSF grant SES 1120976.