Twins on the Way (Harlequin Desire Series #2367)

She's pregnant on his doorstep in this novel from USA TODAY bestselling author Janice Maynard 

Workaholic Cassidy Corelli was a virgin…until her one night with Gavin Kavanagh. Now the daughter of a Vegas mogul has two little problems—the twins she's carrying! When her father disowns her, she's left with only one place to go—back to Gavin. 

But the millionaire's been burned before. He wants a paternity test. Until then, he's determined to keep this woman out of his bed—for his own good. But once he's enjoyed a perfect passion, can a starving man deny himself one more taste?