Ancestry.com on Monday filed with the U.S. Securities and Exchange Commission to go public, intending to raise $75 million.

The aging startup has something Wall Street likes: profits. For the first half of 2009, Ancestry.com reported net income of $8.2 million on revenue of $108 million compared with net income of $1.2 million on revenue of $95 million for the same period a year ago.

Provo, Utah, Ancestry.com is the world’s largest genealogy Web site, counting nearly 1 million paid subscribers as of June 30, up from 460,000 members in January 2004.

Ancestry.com subscribers paid an average of $16.50 per month in the first half of 2009, according to the SEC filing, as subscriber acquisition costs ran $67.30 per member for the period.

Ancestry.com may be the biggest genealogy Web site but it has no shortage of rivals offering similar services for free. MyHeritage, USGenWeb Project, RootsWeb, and Mormon-owned FamilySearch are just a few of the Internet destinations that offer free services.

Spectrum Equity Investors, a private equity firm, wants to cash in on its Ancestry.com investment. Spectrum holds 67 percent of the company’s common stock. Other investors include Crosslink Capital, with 6.2 percent; W Capital Partners, with 6.1 percent; and Sorenson Media, with 5.9 percent.

Ancestry.com took $50 million in venture capital funding between 1998 and 1999 under another moniker, according to Thomson Reuters-owned PE Hub.

Merrill Lynch and Morgan Stanley are the lead underwriters in the offering that counts co-managers Jeffries & Co., Piper Jaffray, and BMO Capital Markets on the ticket.